SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
SECTION IV – HAZARD IDENTIFICATION AND ANALYSIS
44 CFR §201.6(c)(2)(i):
44 Code of Federal Regulations
A description of the type, location, and extent of all natural hazards that can affect the
jurisdiction. The plan shall include information on previous occurrences of hazard
events and on the probability of future hazard events.
Overview
The Hazard Identification and Analysis section identifies and assesses the risk Polk County and the
participating jurisdictions have to a variety of hazards. The Hazard Identification and Analysis Section
consists of two main components: Hazard Identification and Hazard Profiles. The Hazard Identification
section reviews a wide range of hazards and identifies those that could potentially impact the county.
This section includes a description of those hazards with very low or low risk to the county and a
rationale as to why they require no further analyses. The Hazard Profiles section provides information
about how the identified hazards specifically impact the county and participating jurisdictions. The
Vulnerability Assessment and Risk Analysis section (Section V) provides detailed analyses results that
indicate the type and amount of damages that could occur in the county and participating jurisdictions
as a result of the identified hazards. Together, these sections serve to identify, analyze, and assess the
overall risk posed to Polk County and the participating jurisdictions from hazards.
Hazard Identification
Polk County and the participating jurisdictions are vulnerable to a wide range of natural and man-made
hazards that threaten life, property, and the economy. Upon a review of the full range of natural
hazards suggested under FEMA planning guidance, Polk County and the participating jurisdictions have
identified several hazards addressed in this Multi-jurisdictional LMS. In addition, several man-made
hazards are also included. These hazards were identified through an extensive process that utilized
input from the Local Mitigation Strategy Working Group (LMS Working Group) members, research of
past disaster declarations in the county, a review of previous hazard mitigation plans in the county, a
review of the current Florida Hazard Mitigation Plan, and a review of other hazard related documents in
the county. Readily available online information from reputable sources such as federal and state
agencies was also evaluated to supplement information from these key sources.
Hazard Profile
The hazard profiles include a general description of the hazard, its potential impacts, historical
occurrences and the probability of future occurrences. It also includes any specific items noted by
members of the LMS Working Group as it relates to unique historical or anecdotal hazard information
for Polk County or a particular jurisdiction.
Hazard Identification
Tables 4-1 and 4-2 list the full range of hazards initially identified for consideration in the Plan. Table 4-1
includes 15 individual hazards categorized by the following types: atmospheric, hydrologic, geologic,
other natural hazards, and man-made hazards. Some of these hazards are considered to be interrelated
or cascading (i.e., hurricanes can cause flooding and tornadoes), but for preliminary hazard identification
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
purposes, these distinct hazards are broken out separately. It should also be noted that some hazards,
such as drought or winter storms may impact a large area yet cause little damage, while other hazards,
such as a tornado, may impact a small area yet cause extensive damage. Table 4-2 includes a
description of the hazards determined to require no further analyses and the rationale behind the
determination.
TABLE 4-1:
INITIALLY IDENTIFIED HAZARDS AND DETERMINATION OF FURTHER ANALYSIS
Hazard
Further Analysis
Required
No Further Analysis
Required
ATMOSPHERIC HAZARDS
Extreme Temperatures
X
Fog
X
Hurricanes /Tropical Storms
X
Severe Storms and Tornadoes (Hail, Lightning, and
Thunderstorms)
X
Winter Storms
X
GEOLOGIC HAZARDS
Earthquake
X
Landslides
X
Subsidence and Sinkholes
X
Tsunami
X
HYDROLOGIC HAZARDS
Coastal and Riverine Erosion
X
Drought
X
Flood
X
Storm Surge
X
OTHER NATURAL HAZARDS
Climate Change
X
Sea Level Rise
X
Wildfire
X
MAN-MADE HAZARDS
Civil Disturbance/Terrorism
X
Dam/Levee Failure
X
Epidemics
X
Hazardous Material Incidents
X
Mass Immigration/Migration
X
Nuclear/Radiological
X
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
TABLE 4-2:
INITIALLY IDENTIFIED HAZARDS THAT REQUIRE NO FURTHER ANALYSES
EARTHQUAKE
Description
An earthquake is a sudden movement of the Earth's lithosphere (its crust and upper
mantle). Such movements occur along faults, which are thin zones of crushed rock
separating blocks of crust. When one block suddenly slips and moves relative to the
other along a fault, the energy released creates vibrations called seismic waves that
radiate up through the crust to the earth’s surface, causing the ground to shake.
Aftershocks usually follow earthquakes.
Rationale
The U.S. Geological Survey, National Seismic Mapping Project (website), locates Polk
County in the 1% g (0.2 g) peak acceleration area. Because of this very low rating, the
Florida Division of Emergency Management does not require local Comprehensive
Emergency Management Plans to address earthquakes as a hazard that is likely to
affect our residents and visitors. Therefore, this Plan will not include a further
evaluation of this hazard related to vulnerability to people, property, critical
infrastructure, environment, economy, or response operations.
LANDSLIDES
Description
Landslides include a wide range of ground movement, such as rock falls, deep failure
of slopes, and shallow debris flows. Although gravity acting on an over-steepened
slope is the primary reason for a landslide, there are other contributing factors, such
as: Erosion by rivers, glaciers, or ocean waves create over-steepened slopes; Rock and
soil slopes are weakened through saturation by snowmelt or heavy rains; Earthquakes
create stresses that make weak slopes fail; Earthquakes of magnitude 4.0 and greater
have been known to trigger landslides; Volcanic eruptions produce loose ash deposits,
heavy rain, and debris flows; Excess weight from accumulation of rain or snow,
stockpiling of rock or ore, from waste piles, or from man-made structures may stress
weak slopes to failure and other structures.
Rationale
As there has been only one recorded occurrence of a landslide in Florida over 60 years
ago on a very steep slope, and given the low-gradient topography in Polk County, this
Plan will not include a further evaluation of this hazard related to vulnerability to
people, property, critical infrastructure, environment, economy, or response
operations.
TSUNAMI
Description
A series of waves generated by an undersea disturbance such as an earthquake. The
speed of a tsunami traveling away from its source can range from up to 500 miles per
hour in deep water to approximately 20 to 30 miles per hour in shallower areas near
coastlines. Tsunamis differ from regular ocean waves in that their currents travel from
the water surface all the way down to the sea floor. Wave amplitudes in deep water
are typically less than one meter; they are often barely detectable to the human eye.
However, as they approach shore, they slow in shallower water, basically causing the
waves from behind to effectively “pile up”, and wave heights to increase dramatically.
As opposed to typical waves which crash at the shoreline, tsunamis bring with them a
continuously flowing ‘wall of water’ with the potential to cause devastating damage in
coastal areas located immediately along the shore.
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Rationale
Since most tsunamis are associated with major earthquakes, the possibility of a
tsunami affecting the Atlantic or Gulf Coasts of Florida is remote. While the Caribbean
region has a history of both earthquakes and tsunamis, they do not appear to have
affected Florida’s coastlines. Due to Polk County’s inland location, this Plan will not
include a further evaluation of this hazard related to vulnerability to people, property,
critical infrastructure, environment, economy, or response operations
COASTAL AND RIVERINE EROSION
Description
Landward displacement of a shoreline caused by the forces of waves and currents
define coastal erosion. Coastal erosion is measured as the rate of change in the
position or horizontal displacement of a shoreline over a period of time. It is generally
associated with episodic events such as hurricanes and tropical storms, nor’easters,
storm surge and coastal flooding but may also be caused by human activities that alter
sediment transport. Construction of shoreline protection structures can mitigate the
hazard, but may also exacerbate it under some circumstances. In rivers, the erosion of
banks is caused by the scouring action of the moving water, particularly in times of
flood.
Rationale
Polk County is an inland County with no coastline. Therefore, the County is not directly
susceptible to coastal erosion hazards. Polk County contains 554 freshwater lakes that
occupy approximately 135 square miles, while the Hillsborough, Kissimmee,
Palatlakaha, Peace, Alafia, and Withlacoochee rivers wind their way throughout the
county. Erosion is not a hazard and an assessment will be excluded.
STORM SURGE
Description
A storm surge is a large dome of water often 50 to 100 miles wide and rising anywhere
from four to five feet in a Category 1 hurricane up to more than 30 feet in a Category 5
storm. Storm surge heights and associated waves are also dependent upon the shape
of the offshore continental shelf (narrow or wide) and the depth of the ocean bottom
(bathymetry). A narrow shelf, or one that drops steeply from the shoreline and
subsequently produces deep water close to the shoreline, tends to produce a lower
surge but higher and more powerful storm waves. Storm surge arrives ahead of a
storm’s actual landfall and the more intense the hurricane is, the sooner the surge
arrives. Storm surge can be devastating to coastal regions, causing severe beach
erosion and property damage along the immediate coast. Further, water rise caused
by storm surge can be very rapid, posing a serious threat to those who have not yet
evacuated flood-prone areas.
Rationale
Polk County is an inland County with no coastline. The geographical location of Polk
County protects residents from storm surges associated with hurricanes.
CIVIL DISTURBANCE/TERRORISM
Description
Civil disturbances can be generated by a variety of events or conditions. These can
include social unrest, political activism, unstable economic conditions, or radical
antigovernment/anti-establishment movements. While the risk of large-scale civil
disturbances in Polk County is considered low, current trends and indicators suggest
that the potential for civil disturbances at some level will remain present for the mid to
long term period.
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Rationale
Prior to September 11, 2001, the probability of civil disturbance or terrorist activity in
Polk County was considered to be very low. The terrorists attacks on New York and
Washington D.C. resulted in a dramatic increase in the potential threat to the entire
nation and a major change in planning priorities. As of 2012, the threat to Polk County
remains low in relation to other areas in the state where there are major port and
terminal operations and/or military facilities. The uncertainty as to possible terrorist
strategies and targets, and the possible requirement to provide mutual aid support to
other areas, dictates a continuing commitment to planning, training, and acquisition of
resources in support of Homeland Security initiatives in Polk County. Civil
Disturbance/Terrorism is addressed in the County’s CEMP document.
MASS IMMIGRATION/MIGRATION
Description
Mass immigration/migration refers to the migration of large groups of people from
one geographical area to another. Mass migration is distinguished from individual or
small-scale migration; and from seasonal migration, which may occur on a regular
basis.
Rationale
Most of Florida’s mass immigration/migration events result from its proximity to the
Caribbean Basin. Polk County will most likely not serve as either a debarkation
destination for foreign nationals following a Haiti-like earthquake evacuation or as an
immigration point of entry because we do not have a major airport that serves
international flights or a port to receive international shipping.
NUCLEAR/RADIOLOGICAL
Description
A nuclear/radiological incident is a release of radioactive or nuclear material. It may
result from a deliberate act, an accident, or general mismanagement, and may center
around different materials or industrial practices
Rationale
Polk County is outside the 50-mile Emergency Planning Zone (EPZ) for all nuclear
facilities is the State. An evaluation of critical facilities and activities within the County
indicates that it is unlikely that nuclear or radiological devices would be employed
locally.
SEA LEVEL RISE
Description
Sea level, also called mean sea level, is the sea surface level midway between mean
high and low levels, computed from the records of tidal oscillations over a long period.
Relative sea level trends reflect changes in local sea level over time and are typically
the most critical sea level trend for many coastal applications, including coastal
mapping, marine boundary delineation, coastal zone management, coastal
engineering, sustainable habitat restoration design, and public enjoyment of a beach.
Rationale
Polk County is an inland county with no coastline. Based on topography, a 5 meter rise
in sea level would leave Polk County as an inland county while a 50 meter sea level rise
would put all of Polk County except the Lake Wales Ridge and the other high points of
the County under water. Predictions in the planning horizon do not indicate further
evaluation.
WINTER STORMS
Description
Severe winter storms may include snow, sleet, freezing rain, or a mix of these wintry
forms of precipitation. Ice storms occur when moisture falls and freezes immediately
upon impact on trees, power lines, communication towers, structures, roads and other
hard surfaces. Winter storms and ice storms can down trees, cause widespread power
outages, damage property, and cause fatalities and injuries to human life. Extreme
cold temperatures are addressed under Extreme Temperatures.
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Rationale
Snowfall, ice storms, and sleet are very uncommon occurrences in Florida, especially as
far south as Polk County. While winter storms may result in tornadoes, those impacts
are addressed under tornadoes. The impacts of extreme cold temperatures are
addressed under Extreme Temperatures.
Hazard Profile – Atmospheric
Atmospheric Hazards are natural hazards where processes operating in the atmosphere are mainly
responsible.
Extreme Temperatures
Description and Background
The extreme temperature hazard includes both extreme heat and extreme cold. With both these
hazards occurring at a regional geographic level, the entire county is likely to be uniformly exposed to
extreme heat and extreme cold, which are described below:
Extreme Heat:
Temperatures that hover 10 degrees or more above the normal summer high
temperature for the region and last for several weeks are defined as extreme
heat. In Polk County, the normal summer high temperature is 95 degrees. The
heat index may reach up to 115 degrees. Humid or muggy conditions, which
add to the discomfort of high temperatures, occur when a "dome" of high
atmospheric pressure traps hazy, damp air near the ground. Excessively dry and
hot conditions can provoke dust storms and low visibility. Droughts occur when
a long period passes without substantial rainfall. A heat wave combined with a
drought is a very dangerous situation.
Extreme Cold:
Although no specific definition exists for Extreme Cold, the following are
characteristics of an Extreme Cold event: Temperatures at or below freezing for
an extended period of time. Extreme Cold can be both a prolonged period of
excessively cold weather and the sudden invasion of very cold air over a large
area. Along with frost, it can cause damage to agriculture, infrastructure,
property.
Freeze:
According to NOAA’s National Weather Service, a freeze is when surface air
temperatures are expected to be at or below 32 degrees Fahrenheit over a
widespread area for a climatologically significant period of time. Freeze
warnings are issued during the growing season when surface temperatures are
expected to drop below freezing over a large area for an extended period of
time, regardless of whether or not frost develops. Exposure to temperatures
below freezing for extended periods of time may damage or kill crops.
Extreme heat is defined as extended periods of time where the temperature and relative humidity
combine for a dangerous heat index. Extreme heat can occur throughout the state but typically occurs
in the summer between the months of June and September. As illustrated in Figure 4.1, Polk County is
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located in an area with a high summer heat index. This hazard is focused on the affects to the human
population, while drought focuses more in agricultural interests.
Figure 4.1: Severity and Areal Extent of Extreme Summer Heat; Source: FEMA.gov
A heat wave is primarily a public health concern. In 1979, R.G. Steadman, a meteorologist, developed
the Heat Index shown in Table 4-3 to illustrate the risks associated with extreme summer heat. The heat
disorders listed are for the general effect on people in high-risk groups. The Heat Index, also called
apparent temperature, is a measure of how hot it really feels when relative humidity is factored in with
the actual air temperature.
TABLE 4-3:
HEAT DANGER CATEGORIES
Danger Category
Heat Disorders
Apparent
Temperature
(˚F)
Fatigue possible with prolonged exposure and/or physical activity
80-90
Sunstroke, heat cramps, or heat exhaustion possible with
prolonged exposure and/or physical activities
90-105
III. Danger
Sunstroke, heat cramps, or heat exhaustion likely; heat stroke
possible with prolonged exposure and/or physical activity
105-130
IV. Extreme Danger
Heatstroke or sunstroke highly likely with continued exposure
>130
I. Caution
II. Extreme Caution
Source:
NOAA; http://www.srh.noaa.gov/oun/?n=safety-summer-heatindex
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A freeze is weather marked by low temperatures especially when below the freezing point (0˚ Celsius or
32˚ Fahrenheit) for a significant period of time. Freezing temperatures can damage agricultural crops
and burst water pipes in homes and buildings. Frost, often associated with freezes can increase
damaging effects. Frost is a layer of ice crystals that is produced by the deposit of water from the air
onto a surface that is at or below freezing. A freeze warning is issued to make the public and agricultural
interests aware of anticipated freezing conditions over a large area. Similarly, hard freeze is issued under
the same conditions as a freeze warning, but the temperatures may stay well below 28˚ F for a duration
of four hours or more. Certain agricultural crops in Polk County are vulnerable to freezes and
particularly to hard freeze events.
Historical Occurrences
Polk County has a history of severe or disastrous freezes as shown in Table 4-4. Since 1950, there have
been at least 12 recorded severe freezes with the most recent being December 24 and December 25,
1989. A Presidential Disaster Declaration was issued and statewide crop losses exceeded $18,000,000.
In Polk County, damage exceeded $1 million. The freeze affected more than two million acres of
agriculture and citrus products (Florida State Agricultural Stabilization and Conservation Service, 1990).
There was extensive loss of citrus trees and the majority have not been replanted. With several severe
freezes during the 1980s, many growers opted not to re-plant citrus but instead convert the groves to
other uses.
Other notable freezes have resulted in either presidential or agricultural disaster declarations. The
severe freezes in 1982, 1983, and 1985 destroyed crops and citrus trees in Polk and other Central Florida
counties.
According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1968 through 2012, 19
winter weather events occurred. They resulted in one fatality, $70.9 million in crop damages, and
approximately $7.3 million in property damages. Table 4-4 includes the extreme cold/frost/freeze and
heat incidents from 2005 – 2014 as reported by National Climactic Data Center.
1961
Record high temperature of 103 degrees in Avon Park
1981
Record high temperature of 18 degrees in Avon Park
1985
Record high temperature of 20 degrees in Lakeland.
1985
Record high temperature of 103 degrees in Winter Haven.
1989
Record high temperature of 19 degrees in Winter Haven.
October 8, 2009
Record high temperatures of 95 degrees were felt in the Lakeland area
for three days. There was one death as a result of the heat.
2010
Record high temperature of 102 degrees in Lakeland.
TABLE 4-4:
COLD/FROST/FREEZE AND HEAT INCIDENTS
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Date
Type
Location
Death
Injuries
Property
Damage
Crop
Damage
01/23/2005
Frost/Freeze
Polk
0
0
$0
$0
01/15/2006
Cold/Wind Chill
Polk
0
0
$0
$0
01/29/2007
Cold/Wind Chill
Polk
0
0
$0
$0
02/17/2007
Extreme
Cold/Wind Chill
Polk
0
0
$0
$0
01/02/2008
Frost/freeze
Polk
0
0
$0
$0
01/03/2008
Cold/wind Chill
Polk
0
0
$0
$0
10/29/2008
Cold/wind Chill
Polk
0
0
$0
$0
01/21/2009
Frost/freeze
Polk
0
0
$0
$0
01/22/2009
Frost/freeze
Polk
0
0
$0
$0
01/23/2009
Frost/freeze
Polk
0
0
$0
$0
02/05/2009
Frost/freeze
Polk
0
0
$0
$0
02/06/2009
Frost/freeze
Polk
0
0
$0
$0
12/08/2009
Heat
Polk
1
0
$0
$0
01/10/2010
Frost/freeze
Polk
0
0
$0
$13,670,000
02/26/2010
Frost/freeze
Polk
0
0
$0
$1,820,000
12/15/2010
Frost/freeze
Polk
0
0
$0
$8,490,000
01/04/2012
Frost/freeze
Polk
0
0
$0
$0
01/05/2012
Frost/freeze
Polk
0
0
$0
$0
01/15/2012
Frost/freeze
Polk
0
0
$0
$0
02/12/2012
Frost/freeze
Polk
0
0
$0
$0
02/13/2012
Frost/freeze
Polk
0
0
$0
$0
12/23/2012
Frost/freeze
Polk
0
0
$0
$0
Frost/freeze
Polk
0
0
$0
$0
02/18/2013
Source:
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Potential Impacts
Temperature extremes, both freezes and periods of excessive heat, impact communities with a larger
senior population to a greater extent than those with younger populations. Extreme heat can ultimately
cause death. Most heat disorders occur because the victim has been overexposed to heat or has overexercised for his or her age and physical condition. Older adults, young children, and those who are sick
or overweight are more likely to succumb to extreme heat.
As an inland county away from the moderating influence of the ocean or an estuary, Polk County,
especially the areas with significant agricultural assets, is more vulnerable to temperature extremes.
Polk County’s agriculture production is seriously affected when temperatures remain below the freezing
point for four hours or more. A severe freeze can be disastrous. The damage is not limited to total crop
loss, but the plants or trees themselves may also be totally destroyed. Freezes pose a major threat to
the agriculture and citrus crops on a recurring basis. On an average, the state can expect a mild freeze
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every one to two years with major freezes occurring less often. The number of nights with frost and/or
freezing temperatures can vary from 23 to as many as 66 during the winter growing season.
Extreme temperatures can impact power usage and generation; however, it rarely results in structural
losses. The demand for water increases during periods of hot weather. In extreme heat waves, water is
used to cool bridges and other metal structures susceptible to heat failure. This causes a reduced water
supply and pressure in many areas. This can significantly contribute to fire suppression problems for
both urban and rural fire departments. The rise in water temperature during heat waves contributes to
the degradation of water quality and negatively impacts fish populations. It can also lead to the death of
many other organisms in the water ecosystem. High temperatures are also linked to rampant algae
growth, causing fish kills in rivers and lakes. Losses to agriculture would depend on when in the growing
season the impact occurred and could result in less than 10 percent losses or up to 100 percent losses,
depending on the crop coverage. During extended periods of very high temperatures or high
temperatures with high humidity, individuals can suffer a variety of ailments, including heat stroke, heat
exhaustion, heat syncope, and heat cramps. During extended periods of low temperatures, individuals
can suffer hypothermia and frostbite. Those highest at risk are primarily either engaged in outdoor
activity, or are the elderly who are chronically exposed to colder indoor temperatures. Vulnerable
populations include elderly, homeless, and low-income residents. Crops and livestock can also be
vulnerable to extreme heat.
Probability of Future Occurrences
Polk County averages three to four freezes per year with cold fronts occurring approximately every 10 to
14 days throughout the winter. The frequency of extreme heat events is likely to be once every two to
seven years based on the naturally occurring El Niño/La Niña cycle. In Florida, La Niña years are
characterized by reduced rainfall and higher temperatures. While the County historically experiences
events of extreme temperatures annually, there are generally no damages associated with these events.
The hazards associated with such events primarily affect very young or elderly residents or transient
populations. Sustained episodes of high heat can result in illness and fatalities in susceptible
populations. Given the demographic trends experienced in the county, this potential hazard is expected
to increase. There have been no recorded occurrences of extreme summer heat impacting Polk County
to the extent that response actions beyond public service announcements to provide general guidance
to avoid heat stroke need to be taken.
Fog
Description and Background
Fog comprises dense clouds of water droplets immediately
above land or water surfaces. Radiation fog occurs as a
result of heat loss by radiate cooling of moist air. Advection
fog occurs where warm, moist air moved over a cold surface
or cold air moves over a body of warm water. Fog is
generally a danger where visual sensing and signals are
essential to safe activity or operations (Hewitt, Kenneth).
Thick masses of fog are often dense and can rapidly drop
visibility levels. Unlike tornadoes or floods, the fog itself
4.2: Fog on US 98 near Bartow Source:
does harm only indirectly, when movement of persons and Figure
Marisa M. Barmby
goods is paralyzed, seriously reduced, or slowed down
(Hewitt, Kenneth). Fog incidents can occur throughout the entire county.
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Historical Occurrences
January 9, 2008
A mixture of fog and smoke from a prescribed burn covered portions of
Interstate-4 causing seventy cars and trucks to collide near mile marker 47
resulting in five deaths and 38 injuries.
According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1960 through 2012, three
severe fog events occurred. They resulted in two fatalities and approximately $967,000 in property
damages as reported by the National Climactic Data Center. Table 4-5 includes the fog incidents from
2000 – 2014 as reported by National Climactic Data Center.
TABLE 4-5:
FOG INCIDENTS BY JURISDICTION
Date
Location
Death
Injuries
01/30/2000
Polk
0
0
$0
$0
02/15/2000
Polk
0
0
$0
$0
02/02/2001
Polk
0
0
$0
$0
02/06/2001
Polk
1
0
$350,000
$0
02/10/2001
Polk
0
0
$0
$0
02/11/2001
Polk
0
0
$0
$0
02/12/2001
Polk
0
0
$0
$0
02/14/2001
Polk
0
0
$0
$0
02/27/2001
Polk
0
0
$0
$0
02/27/2001
Polk
0
0
$0
$0
05/28/2001
Polk
1
0
$300,000
$0
12/09/2001
Polk
0
0
$0
$0
01/20/2002
Polk
0
0
$0
$0
01/21/2002
Polk
0
0
$0
$0
01/22/2002
Polk
0
0
$0
$0
Polk
0
0
$0
$0
01/09/2008
Source:
Property
Damage
Crop Damage
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Potential Impacts
Foggy conditions promote accidents because of low visibility and the impact on a driver’s perceptual
judgments of speed and distance. Foggy conditions can lead to chain-reaction accidents, which can
cause property damage and loss of life. As illustrated in Figure 4.3, the I-4 corridor running through Polk
County has a high density of fog related crashes. There are a variety of road sections, intersections, and
rail crossings in the county that are more susceptible to impacts of foggy conditions. They are outlined
in the Vulnerability Analysis for Fog in Section V.
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Figure 4.3: 2006-2010 Florida Fog Related Crash Density Source: FDOT
Probability of Future Occurrences
Fog events occur in Polk County every year. According to Geography Hunter and FDOT, Central Florida
and Polk County can expect to experience 15 to 20 days per year with heavy fog with fog events more
likely to occur in cold months. Due to the historical crash related density and the number of heavy fog
event days, Polk County can expect to experience 15 to 20 days with heavy fog which leads to increased
changes of possible accidents. The probability of future occurrences of fog creating significant impacts is
moderate.
Hurricanes and Tropical Storms
Description and Background
Hurricanes and tropical storms are
classified as cyclones and defined as
any closed circulation developing
around a low-pressure center in which
the winds rotate counter-clockwise in
the Northern
Hemisphere (or clockwise in the
Southern Hemisphere) and whose
diameter averages 10 to 30 miles
across. A tropical cyclone refers to any
such circulation that develops over
tropical waters. Tropical cyclones act
as a “safety-valve,” limiting the
Figure 4.4: Hurricane Charley damage at Quails Bluff Apartments in
Lake Wales; Source: The Tampa Tribune, 2004
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continued build-up of heat and energy in tropical regions by maintaining the atmospheric heat and
moisture balance between the tropics and the pole-ward latitudes. The primary damaging forces
associated with hurricanes and tropical storms are high-level sustained winds, heavy precipitation, and
tornadoes. Coastal areas are also vulnerable to the additional forces of storm surge, wind-driven waves,
and tidal flooding, which can be more destructive than cyclone wind.
The key energy source for a tropical cyclone is the release of latent heat from the condensation of warm
water. Their formation requires a low-pressure disturbance, warm sea surface temperature, rotational
force from the spinning of the earth and the absence of wind shear in the lowest 50,000 feet of the
atmosphere. The majority of hurricanes and tropical storms form in the Atlantic Ocean, Caribbean Sea,
and Gulf of Mexico during the official Atlantic hurricane season, which encompasses the months of June
through November. The peak of the Atlantic hurricane season is in early to mid-September, and the
average number of storms that reach hurricane intensity per year in this basin is about six.
As an incipient hurricane develops, barometric pressure (measured in millibars or inches) at its center
falls and winds increase. If the atmospheric and oceanic conditions are favorable, it can intensify into a
tropical depression. When maximum sustained winds reach or exceed 39 miles per hour, the system is
designated a tropical storm, given a name, and is closely monitored by the National Hurricane Center in
Miami, Florida. When sustained winds reach or exceed 74 miles per hour the storm is deemed a
hurricane. Hurricane intensity is further classified by the Saffir-Simpson Scale which rates hurricane
intensity on a scale of 1 to 5, with 5 being the most intense. The Saffir-Simpson Scale categorizes
hurricane intensity linearly based upon maximum sustained winds, barometric pressure and storm surge
potential, which are combined to estimate potential damage. Categories 3, 4, and 5 are classified
“major” hurricanes. Hurricanes within this range comprise only 20 percent of total tropical cyclone
landfalls, but they account for over 70 percent of the damage in the United States.
Hurricanes and tropical storms threaten the entire Atlantic and Gulf seaboard of the United States.
Coastal areas are directly exposed to the brunt of a landfalling storm, but its impact is often felt
hundreds of miles inland. All areas of Polk County are susceptible to the accompanying hazard effects
including extreme wind, flooding, and tornadoes.
Historical Occurrences
The most prominent occurrences of hurricane and tropical storms occurred in 2004 when Polk County
was directly impacted by three hurricanes (Charley, Frances, and Jeanne), while indirectly affected by
one (Ivan) other. Hurricane Charley made landfall on August 13th, Frances on September 4th, Ivan on
September 16th, and hurricane Jeanne on September 26th. Total damages in Polk County are still being
determined. The population of Polk County at the time was around 510,458 residents. Outside of the
2004 season, hurricanes Erin (1995), Irene (1999), Wilma (2005), and Ernesto (2006), along with Tropical
Storms Jerry (1995), Mitch (1998), and Fay (2008) have impacted the county within the last 15 years
(Source: Polk County Emergency Operations Center, NOAA).
August 13, 2004
Hurricane Charley (FEMA declaration #1539-DR)
September 5, 2004
Hurricane Frances (FEMA declaration #1545-DR)
September 16, 2004
Hurricane Ivan struck west Florida. The remnants of the storm impacted Polk
County.
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September 26, 2004
Hurricane Jeanne (FEMA declaration #1561-DR)
2005
Hurricane Wilma
The County felt the impacts of Hurricane Wilma and received a declaration of
Public Assistance (FEMA declaration #1609-DR)
2008
Tropical Storm Fay
The County felt the impacts of Tropical Storm Fay and received a declaration of
Individual Assistance (FEMA declaration #1785-DR)
According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1960 through 2012, 24
hurricane/tropical storm events occurred. They resulted in 53 injuries, 1 fatality, approximately $75.6 in
crop damages, and approximately $401 million in property damages. In addition to the information
above, Table 4-7 includes the hurricane and tropical storm incidents between 2000 to 2008 as indicated
by the National Climatic Data Center.
Figure 4.5: Hurricane Tract Chart; Source: Economic Disaster Resiliency Study
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TABLE 4-7:
HURRICANE/TROPICAL STORM INCIDENTS BY JURISDICTION
Date
Location
Deaths
Injuries
9/17/2000
Polk County
0
0
$25,000
$0
9/14/2001
Polk County
0
0
$100,000
$0
10/24/2005
Polk County
0
0
$405,000
$0
6/2/2007
Polk County
0
0
$0
$0
Polk County
0
0
$0
$0
8/19/2008
Source:
Property
Damage
Crop
Damage
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Potential Impacts
Florida is the most vulnerable state in the nation to the impacts of hurricanes and tropical storms.
Hurricane season runs from June through November. From June through July, and again in late October,
the regions of maximum hurricane activity are the Gulf of Mexico and the western Caribbean. In Polk
County, the primary effects from a hurricane are high winds and inland flooding. Tornadoes associated
with tropical storms are most frequent in September and October when the incidence of tropical storms
is greatest. Inland flooding is likely during any hurricane due to low elevation of much of the County.
Tall structures, like radio towers, can be destroyed by hurricane force winds; some structures, such as
mobile homes, are particularly at risk.
Probability of Future Occurrences
According to NOAA’s website, Central Florida has a 50% probability of being struck by a named storm.
Recent history indicates that residents can expect a storm to affect Polk County every 2-3 years, and the
most likely event will be a Category 3 or lesser storm. The probability of being affected by a storm is low
to moderate.
Severe Storms and Tornadoes (Hail, Lightning, and Thunderstorms)
Severe storms and tornadoes share the components of hail, lightning, and thunderstorms. While they
are all related, they can happen independently of each other. This section includes a discussion of each
of the components.
Description and Background
Hail
Hail frequently accompanies thunderstorms and has potential to cause substantial damage. Early in the
developmental stages of hail, ice crystals form within a low-pressure front due to the rapid rising of
warm air into the upper atmosphere and the subsequent cooling of the air mass. Frozen droplets
gradually accumulate on the ice crystals until they develop sufficient weight to fall as precipitation. Hail
precipitation falls in sphere or irregularly shaped masses greater than 0.75 inches in diameter. The size
of hailstones is a direct function of the size and severity of the storm. High velocity updraft winds are
required to keep hail in suspension in thunderclouds. The strength of the updraft is a function of the
intensity of heating at the Earth’s surface. Higher temperature gradients relative to elevation above the
surface result in increased suspension time and hailstone size. Hailstones grow in size when the frozen
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droplet is repeatedly blown into the higher elevations. The hailstone ascends as long as the updraft
velocity is high enough to hold the hailstone. As soon as the size and weight of the hailstone overcome
the lifting capacity of updraft, it begins to fall freely under the influence of gravity. The falling of
hailstones, under thunderstorm conditions, is accompanied with a cold downdraft of air. Table 4-8
illustrates the Torro Hailstorm Intensity Scale which outlines the typical damage impacts based on hail
intensity.
TABLE 4-8:
THE TORRO HAILSTORM INTENSITY SCALE (H0 to H10)
Intensity Category
Typical Hail
Diameter
(mm)*
Typical Damage Impacts
H0
Hard Hail
5
No damage
H1
Potentially Damaging
5-15
Slight general damage to plants, crops
H2
Significant
10-20
Significant damage to fruit, crops, vegetation
H3
Severe
20-30
Severe damage to fruit and crops, damage to glass and
plastic structures, paint and wood scored
H4
Severe
25-40
Widespread glass damage, vehichle bodywork damage
H5
Destructive
30-50
Wholesale destruction of glass, damage to tiled roofs,
significant risk of injuries
H6
Destructive
40-60
Bodywork of grounded aircraft dented, brick walls
pitted
H7
Destructive
50-75
Severe roof damage, risk of serious injuries
H8
Destructive
60-90
Severe damage to aircraft bodywork
H9
Super Hailstorms
75-100
Extensive structural damage. Risk of severe or even
fatal injuries to persons caught in the open
H10
Super Hailstorms
>100
Extensive structural damage. Risk of severe or even
fatal injuries to persons caught in the open
*
Approximate range (typical maximum size in bold), since other factors (e.g. number and density of hailstones, hail fall
speed and surface wind speeds) affect severity.
Hail is often produced during a
thunderstorm event, which has no
geographic limitations to the area it affects.
Therefore, it is assumed that all of Polk
County is uniformly at risk to a hail event.
Impacts typically include downed power
lines and trees and damage to vehicles and
mobile homes.
Hailstorms are an outgrowth of severe
thunderstorms and cause nearly $1 billion in
damage to property and crops on an annual
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Figure 4.6: Hail Storm; Source: Globe Views, http://golbeviews.com/dreams/hail.html Photographer unknown
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
basis in the US. Typical thunderstorms can be 3 miles wide at the base, rise to 40,000 to 60,000 feet in
the troposphere, and contain half a million tons of condensed water. Hailstorms are violent and
spectacular phenomena of atmospheric convection, always associated with heavy rain, gusty winds,
thunderstorms, and lightning. Hail is a product of strong convection and occurs only in connection with
a thunderstorm where the high velocity updrafts carry large raindrops into the upper atmosphere
(where the temperature is well below the freezing point of water).
Lightning
Lightning is a discharge of electrical energy resulting from the buildup of positive and negative charges
within a thunderstorm, creating a “bolt” when the buildup of charges becomes strong enough. This
flash of light usually occurs within the
clouds or between the clouds and the
ground. A bolt of lightning can reach
temperatures approaching 50,000 degrees
Fahrenheit. Lightning rapidly heats the sky
as it flashes, but the surrounding air cools
following the bolt. This rapid heating and
cooling of the surrounding air causes
thunder, which often accompanies
lightning strikes.
While most often
affiliated with severe thunderstorms,
lightning often strikes outside of heavy
rain and might occur as far as 10 miles
away from any rainfall.
Figure 4.7: Lightning; Source: Shutterstock
On average, 73 people are killed each year
by lightning strikes in the United States. Central Florida is the most lightning prone area in the United
States with about 90 thunderstorm days a year. Because of this, Florida has more lightning deaths than
any other state. In fact, lightning kills more people in Florida than all other weather hazards combined.
In the Florida peninsula thunderstorm season has two general periods. The summer months, from early
May to early October are known as the wet season. Conversely, October through May is known as the
dry season. Historically, the most dangerous months are June, July and August. This is due to an
abundance of moisture, atmospheric instability, and storm triggering sea breezes. Moisture is almost
always available in the summer because Florida is a peninsula with the Gulf of Mexico to the west and
the warm Atlantic Gulfstream to the east. Instability is a function of surface heat and cool air aloft,
something present for most of the summer season. Finally, a trigger is needed to get thunderstorms
going. This is provided daily in the form of the sea breeze that forms on the Atlantic and Gulf coasts. As
a sea breeze forms, it typically moves inland (from the Atlantic or Gulf of Mexico) and dramatically aids
thunderstorm formation. Surface winds also play a big part in determining which areas get the most
lightning and at what time they get it. With westerly morning winds across the peninsula, afternoon
thunderstorms tend to pile up on the east coast. If the morning winds are from the east, afternoon
thunderstorms will cluster on the west coast.
Lightning seeks the path of least resistance on its way to and through the ground. The human body is an
extremely good conductor because of its large water content. Metal is a better conductor than most
objects so lightning can travel easily through metal objects such as fences or railroad tracks, which can
conduct electricity for long distances.
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Polk County is located in a region of the country that is particularly susceptible to lightning. Figure 4.8
shows a lightning flash density per square mile map for the years 1997-2010 based upon data provided
by Vaisala’s U.S. National Lightning Detection Network (NLDN®). Lightning occurs randomly and is,
therefore, impossible to predict where it will strike. It is assumed that all of Polk County is uniformly
exposed to lightning which strikes in very small, specific geographic areas.
Figure 4.8: Flash Density per Square Mile 1997-2010; Source: Vaisala.com
As part of the lightning capital of the United States, Polk County has experiences several occurrences
with lightning, many of which have caused property damage or resulted in death. Figure 4.9 illustrates
that between 1959 and May 2014, Polk County experienced the fifth most lightning deaths in Florida.
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Figure 4.9: Florida Lightning Deaths 1959-2014; Source: Hernandosheriff.org
Thunderstorms
Thunderstorms are caused by air masses of varying temperatures meeting in the atmosphere. Rapidly
rising warm moist air fuels the formation of thunderstorms. Thunderstorms may occur singularly, in
lines, or in clusters. They
can move through an area
very quickly or linger for
several hours.
Thunderstorms
are
common
throughout
Florida
and
occur
throughout the year.
Although thunderstorms
generally affect a small
area, they are very
dangerous given their
ability
to
produce
accompanying
hazards
including high winds, hail,
Figure 4.10: Storm in Lakeland on March 31, 2011. Source: YouTube, Photographer:
and lightning, which all
Kisha Hartman
may cause serious injury
or death, in addition to property damage. According to the National Weather Service, more than
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100,000 thunderstorms occur each year, though only about 10 percent of these storms are classified as
“severe.” A severe thunderstorm occurs when the storm produces one of three elements: 1) hail of
three-quarters of an inch; 2) tornado; 3) winds of at least 58 miles per hour.
Three conditions need to occur for a thunderstorm to form. First, it needs moisture to form clouds and
rain. Second, it needs unstable air, such as warm air that can rise rapidly (this often referred to as the
“engine” of the storm). Finally, thunderstorms need lift, which comes in the form of cold or warm
fronts, sea breezes, mountains, or the sun’s heat. When these conditions occur, air masses of varying
temperatures meet, and a thunderstorm is formed. These storm events can occur singularly, in lines, or
in clusters. Further, they can move through an area very quickly or linger for several hours.
The National Weather Service collected data for thunder events and lightning strike density for the 30year period from 1948 to 1977. A series of maps were generated showing the annual average thunder
event duration, the annual average number of thunder events, and the mean annual density of lightning
strikes. Figure 4.11 illustrates thunderstorm hazard severity based on the annual average number of
thunder events from 1948 to 1977. Polk County falls into the range of an average of 110 – 120
thunderstorm events annually.
Figure 4.11: Thunderstorm hazard severity based on the annual average number of thunder events from
1948-1977; Source: www.fema.gov
Table 4-9 illustrates the Beaufort Wind Force Scale which is an empirical measure that related wind
speed to observed conditions at sea of on land.
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TABLE 4-9:
THE BEAUFORT WIND FORCE SCALE – EFFECTS ON LAND
Force
Wind (Knots)
WMO
Classification
Appearance of Wind Effects On Land
0
Less than 1
Calm
Calm, smoke rises vertically
1
1-3
Light Air
Smoke drift indicates wind direction, still wind vanes
2
4-6
Light Breeze
Wind felt on face, leaves rustle, vanes begin to move
3
7-10
Gentle Breexe
Leaves and small twigs constantly moving, light flags
extended
4
11-16
Moderate Breeze
Dust, leaves, and loose paper lifted, small tree
branches move
5
17-21
Fresh Breeze
Small trees in leaf begin to sway
6
22-27
Strong Breeze
Larger tree branches moving, whistling in wires
7
28-33
Near Gale
Whole trees moving, resistance felt walking against
wind
8
34-40
Gale
Twigs breaking off trees, generally impedes progress
9
41-47
Strong Gale
Slight structural damage occurs, slate blows off roofs
10
48-55
Storm
Seldom experienced on land, trees broken or uprooted
11
56-63
Violent Storm
Widespread damage
12
64+
Hurricane
Structural damage
Severe thunderstorms and their related hazardous elements (including lightning, hail, and straight-line
winds) are not confined to any geographical boundaries and typically are widespread events. Further,
while thunderstorms can occur in all regions of the United States, they are most common in the central
and southern states because atmospheric conditions in those regions are favorable for generating these
powerful storms. Therefore, it is assumed that Polk County would be uniformly exposed to these
hazards and that the spatial extent of that impact would potentially be large.
Tornadoes
A tornado is a violently rotating column of air that has contact with the ground and is often visible as a
funnel cloud. Its vortex rotates cyclonically with wind speeds ranging from as low as 40 mph to as high
as 300 mph. Tornadoes are most often generated by thunderstorm activity when cool, dry air intersects
and overrides a layer of warm, moist air forcing the warm air to rise rapidly. The destruction caused by
tornadoes ranges from light to catastrophic depending on the intensity, size, and duration of the storm.
In general, the tornados that occur in Florida are less intense than those that occur in the Great Plains
(see the Enhanced Fujita Intensity Scale below) but can produce substantial damage.
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The majority of tornados, 69 percent, are weak tornados, EF0-EF2 categories. Approximately 29 percent
of all tornados are strong and
can last 20 minutes or longer.
Approximately 2 percent of all
tornados fall into the EF-4 and
EF-5 categories.
The most
powerful tornados are spawned
by what are called supercell
thunderstorms.
These are
storms that, under the right
conditions, are affected by
horizontal wind shears (winds
moving in different directions at
different altitudes). These wind
shears cause horizontal columns
of air to begin to rotate. This
horizontal rotation can be tilted
Figure 4.12: Severe Thunderstorms and Suspect Tornado Cause Damage at
vertically by violent updrafts,
Lakeland Linder Airport. Source: Orlando Sentinel; Courtesy of Michael Daniels
and the rotation radius can
shrink, forming a vertical column
of very quickly swirling air. This rotating air can eventually reach the ground, forming a tornado. At
present, there is no way to predict exactly which storms will spawn tornados or where the tornados will
touch down. Doppler radar systems have greatly improved the forecaster's warning capability, but the
technology usually provides lead times from only a few minutes up to about 30 minutes. Consequently,
early warning systems and preparedness actions are critical.
The Enhanced Fujita Tornado Damage Scale (Enhanced F-scale) is a set of wind estimates (not
measurements) based on damage (Table 4-10). It uses three-second gusts estimated at the point of
damage based on a judgment of eight levels of damage. These estimates vary with height and exposure.
The three second gust is not the same wind as in standard surface observations. Standard
measurements are taken by weather stations in open exposures, using a directly measured "one minute
mile" speed.
TABLE 4-10:
THE ENHANCED FUJITA INTENSITY SCALE
Category
Wind Speed
Potential Damage
EF-0
65 – 85 mph
Light damage. Peels surface off some roofs; some damage to
gutters or siding; branches broken off trees; shallow-rooted trees
pushed over.
EF-1
86 – 110 mph
Moderate damage. Roofs severely stripped; mobile homes
overturned or badly damaged; loss of exterior doors; windows and
other glass broken.
EF-2
111 – 135 mph
Considerable damage. Roofs torn off well-constructed houses;
foundations of frame homes shifted; mobile homes completely
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TABLE 4-10:
THE ENHANCED FUJITA INTENSITY SCALE
Category
Wind Speed
Potential Damage
destroyed; large trees snapped or uprooted; light-object missiles
generated; cars lifted off ground.
EF-3
136 – 165 mph
Severe damage. Entire stories of well-constructed houses
destroyed; severe damage to large buildings such as shopping
malls; trains overturned; trees debarked; heavy cars lifted off the
ground and thrown; structures with weak foundations blown away
some distance.
EF-4
166 – 200 mph
Devastating damage. Whole frame houses Well-constructed
houses and whole frame houses completely leveled; cars thrown
and small missiles generated.
EF-5
> 200 mph
Incredible damage. Strong frame houses leveled off foundations
and swept away; automobile-sized missiles fly through the air in
excess of 100 m (109 yd); high-rise buildings have significant
structural deformation; incredible phenomena will occur
Historical Occurrences
Hail
Incorporated areas of Polk County have experienced slightly more hail events than the unincorporated
Polk County, 56 percent and 44 percent, respectively. Of the incorporated jurisdictions, the City of
Lakeland has experienced the most hail events in the County, followed by Winter Haven, Auburndale,
and Mulberry.
Severe Storm Hail Events by Jurisdiction
45
40
35
30
25
20
15
10
5
0
Figure 4.13: Severe Storm Hail Events; Source: SHELDUS
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According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1960 through 2012, 26 hail
events occurred. They resulted in two injuries, approximately $6,000 in crop damages, and
approximately $45.6 million in property damages. Due to the high number of incidents (107 incidents
between 2000 and 2014) reported by the National Climactic Data Center, Table 4-11 includes the hail
incidents from 2010 – 2014.
TABLE 4-11:
HAIL INCIDENTS BY JURISDICTION
Date
Location
Magnitude
Deaths
Injuries
3/11/2010
Polk County
0.88 in.
0
0
$0
$0
06/03/2010
Polk County
0.88 in.
0
0
$0
$0
06/03/2010
Polk County
1.00 in.
0
0
$0
$0
06/17/2010
Polk County
0.88 in.
0
0
$0
$0
05/13/2011
Polk County
1.00 in.
0
0
$0
$0
05/13/2011
Polk County
1.25 in.
0
0
$0
$0
06/12/2011
Polk County
1.00 in.
0
0
$0
$0
06/15/2011
Polk County
1.00 in.
0
0
$0
$0
06/15/2011
Polk County
1.00 in.
0
0
$0
$0
06/15/2011
Polk County
0.75 in.
0
0
$0
$0
06/21/2011
Polk County
0.75 in.
0
0
$0
$0
05/18/2012
Polk County
1.00 in.
0
0
$0
$0
06/10/2013
Polk County
0.88 in.
0
0
$0
$0
06/20/2013
Polk County
0.88 in.
0
0
$0
$0
05/29/2014
Polk County
1.00 in.
0
0
$0
$0
06/15/2014
Polk County
1.75 in.
0
0
$0
$0
06/15/2014
Polk County
1.50 in.
0
0
$0
$0
07/20/2014
Polk County
0.75 in.
0
0
$0
$0
Polk County
1.00 in.
0
0
$0
$0
08/07/2014
Source:
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Property
Damage
Crop
Damage
Lightning
According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1960 through 2012, 77
lightning events occurred. They resulted in 72 injuries, 25 fatalities, approximately $11,000 in crop
damages, and approximately $3.1 million in property damages. The National Climatic Data Center
reports the lightning incidents from 2000 – 2014 as provided in Table 4-12.
TABLE 4-12:
LIGHTNING INCIDENTS BY JURISDICTION
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Date
Jurisdiction
Death
Injuries
06/24/2000
Lakeland
0
1
$0
$0
7/20/2000
Haines City
0
1
$0
$0
09/03/2000
Bartow
0
1
$0
$0
05/29/2002
Lakeland
0
0
$20,000
$0
06/21/2003
Mulberry
1
1
$0
$0
5/18/2005
Bartow
0
0
$1,000,000
$0
6/7/2005
Lakeland
0
0
$46,000
$0
6/23/2005
Lakeland
0
1
$0
$0
8/4/2005
Dundee
0
1
$10,000
$0
7/27/2006
Unincorporated
Polk County
(Gibsonia)
0
1
$0
$0
6/25/2007
Frostproof
0
1
$0
$0
6/22/2008
Lakeland
0
0
$2,000
$0
5/14/2009
Bartow
0
0
$190,000
$0
6/16/2009
Davenport
0
0
$50,000
$0
7/4/2009
Unincorporated
Polk County
(Winston)
1
26
$0
$0
3/11/2010
Lakeland
0
0
$0
$0
8/27/2011
Unincorporated
Polk County
(Carters
Corner)
0
9
$0
$0
5/18/2012
Lakeland
Highlands
0
1
$0
$0
9/7/2012
Unincorporated
Polk County
(Providence)
1
0
$0
$0
Source:
Property
Damage
Crop Damage
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Thunderstorms
According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1960 through 2012, 192
severe storm events occurred. They resulted in 13 injuries, 2 fatalities, approximately $3.2 million in
crop damages, and approximately $14.6 million in property damages. Due to the high number of
incidents, Table 4-13 includes the severe storm incidents from 2010 – 2014 as reported by National
Climactic Data Center.
TABLE 4-13:
SEVERE STORM INCIDENTS BY JURISDICTION
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August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Date
Location
Magnitude
Injuries
Property
Damage
Crop
Damage
0
0
$2,000
$0
0
0
$0
$0
3/11/2010
Auburndale
3/11/2010
Lakeland
3/12/2010
Haines City
43 kts. EG
0
0
$5,000
$0
4/26/2010
Fort Meade
43 kts. EG
0
0
$2,000
$0
6/3/2010
Highland City
55 kts. EG
0
0
$112,500
$0
7/28/2010
Wahneta
48 kts. EG
0
0
$900,000
$0
1/25/2011
Winston
43 kts. EG
0
0
$10,000
$0
3/31/2011
Cypress Gardens
52 kts. EG
0
0
$2,000
$0
3/31/2011
Jack Browns Seaport
63 kts. MG
0
0
$0
$0
3/31/2011
Lakeland Highlands
57 kts. EG
0
0
$0
$0
4/5/2011
Crystal Lake
50 kts. EG
0
0
$2,000
$0
5/13/2011
Auburndale
52 kts. EG
0
0
$0
$0
6/15/2011
Jack Browns Seaport
55 kts. MG
0
0
$0
$0
6/17/2011
Alcoma
50 kts. EG
0
0
$2,000
$0
6/23/2011
Fort Meade
50 kts. EG
0
0
$3,000
$0
8/27/2011
Auburndale
0
0
$500
$0
6/24/2012
Eloise
1
4
$0
$0
5/20/2013
Fort Meade
50 kts. EG
0
0
$0
$0
7/22/2013
North Winter Haven
40 kts. EG
0
0
$5,000
$0
8/21/2013
(Lal)Lakeland Muni A
51 kts. MG
0
0
$0
$0
8/21/2013
Gordonville
52 kts. EG
0
0
$0
$0
8/21/2013
Lakeland
50 kts. EG
0
0
$0
$10,000
2/12/2014
Armour
40 kts. EG
0
0
$2,000
$0
2/12/2014
Davenport
43 kts. EG
0
0
$15,000
$0
2/12/2014
Pembroke
43 kts. EG
0
0
$3,000
$0
3/29/2014
Lake Marion Lake
60 kts. EG
0
0
$100,000
$0
6/10/2014
Auburndale
45 kts. EG
0
0
$1,000
$0
6/16/2014
Winter Haven
50 kts. EG
0
0
$2,000
$0
6/21/2014
Lake Weohyakapka
50 kts. EG
0
0
$1,000
$0
6/26/2014
Bartow
45 kts. EG
0
0
$25,000
$0
6/26/2014
Fort Meade
40 kts. EG
0
0
$5,000
$0
6/27/2014
Lake Rosalie
40 kts. EG
0
0
$1,000
$0
9/26/2014
Mulberry Circle X Ar
0
0
$5,000
$0
9/26/2014
Willow Oak
0
0
$10,000
$0
9/27/2014
Mulberry Circle X Ar
0
0
$0
$0
Source:
43 kts. EG
Deaths
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Tornadoes
April 15, 1958
The April 1958 Florida tornado outbreak was a severe weather event
that primarily affected the Florida peninsula. Of the tornadoes included
in this event, approximately 75 percent of the Florida events attained F3
intensity or greater. The strongest tornado produced F4 damage on the
Fujita scale in Polk County, becoming one of only two F4 tornadoes
recorded in Florida. According to NOAA, the event injured seven people
and created approximately $25,000 in property damages.
April 4, 1966
The deadly 1966 Tampa tornado family affected the I-4 corridor in
Central Florida from the Tampa Bay area to Brevard County on April 4,
1966. Two tornadoes affected the region, each of which featured a
path length in excess of 100 miles (160 km). One of the tornadoes
produced estimated F4 damage on the Fujita scale; it remains one of
only two F4 tornadoes to strike the U.S. state of Florida, the other of
which occurred in 1958. According to NOAA, the event killed eight
people in Polk County, injured 450 people, and created approximately
$25 million in property damages. A non-tropical cyclone is credited with
inducing the event.
According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1958 through 2012, 124
tornado events occurred. They resulted in 186 injuries, three fatalities, approximately $21,500 in crop
damages, and approximately $53.2 million in property damages. Table 4-14 includes the tornado
incidents from 2000 – 2014 as reported by National Climactic Data Center.
TABLE 4-14:
TORNADO INCIDENTS BY JURISDICTION
Date
Location
Magnitude
Death
Injuries
Property
Damage
6/27/2000
Mulberry
F0
0
0
$20,000
$0
7/30/2000
Lakeland
F0
0
0
$25,000
$0
5/17/2002
Haines City
F0
0
0
$20,000
$0
7/11/2002
Winter Haven
0
0
$0
$0
7/25/2002
Highland City
F0
0
0
$20,000
$0
8/14/2002
Lakeland Municipal
Airport
F0
0
0
$0
$3,000
5/24/2003
Mulberry
F0
0
0
$0
$0
2/24/2004
Auburndale
F0
0
0
$10,000
$0
8/13/2004
Davenport
F0
0
0
$0
$0
8/13/2004
Lake Wales
F0
0
0
$0
$0
9/4/2004
Kathleen
F0
0
0
$0
$0
9/6/2004
Bartow
F0
0
0
$0
$0
4/23/2005
Mulberry
F1
0
0
$250,000
$0
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Polk County Multi-jurisdictional Local Mitigation Strategy
Crop
Damage
August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
TABLE 4-14:
TORNADO INCIDENTS BY JURISDICTION
Date
Location
Magnitude
Death
Injuries
6/30/2005
Highland City
F0
0
0
$0
$0
8/12/2005
Frostproof
F0
0
0
$0
$0
10/23/2005
Mulberry
F0
0
0
$10,000
$0
6/12/2006
Bartow
F0
0
0
$0
$0
6/24/2006
Lakeland
F0
0
0
$0
$0
7/24/2006
Lakeland
0
0
$0
$0
9/15/2006
Frostproof
F0
0
0
$0
$0
2/2/2007
Frostproof
EF0
0
0
$2,000
$0
4/15/2007
Dundee
EF0
0
0
$250,000
$0
8/22/2008
Lake Rosalie
EF0
0
0
$30,000
$0
5/12/2009
Lake Parker
EF0
0
0
$15,000
$0
8/12/2009
Auburndale
EF0
0
0
$35,000
$0
3/11/2010
Auburndale
EF0
0
0
$2,000
$0
3/11/2010
Lake Marion Lake
EF1
0
0
$200,000
$0
3/31/2011
Lakeland Municipal
Airport
EF1
0
0
3/31/2011
Prairie
EF0
0
0
$5,000
$0
3/31/2011
Socrum
EF0
0
0
$0
$0
6/24/2012
Winter Haven Cypress
Gardens Area
EF0
0
0
6/24/2012
Winter Haven Cypress
Gardens Area
EF2
0
0
Source:
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Property
Damage
$500,000
$4,000
$390,000
Crop
Damage
$0
$0
$0
Potential Impacts
Hail
Hail can cause damage to structures, vehicles, and crops. The larger the hail, the more damage it can
cause. An analysis of the event information provided by SHELDUS results in the majority of the hail
events in the county resulting in penny to nickel sized hail. Approximately 18 percent of the hail events
were measured between 1.25 inches and 4.5 inches. These hail sizes can result in significantly more
damage to structures, vehicles, and crops. A discussion of the impacts to specific assets is included in
the vulnerability section (Section V).
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August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Severe Storm Hail Sizes
16%
2%
56%
26%
0.75 - 0.88 (Penny to Nickel)
0.88 - 1.25 (Nickel to Half Dollar)
1.25 - 2.00 (Half Dollar to Hen Egg)
2.00 - 4.50 (Hen Egg to Softball)
Figure 4.14: Severe Hail Storm Sizes; Source: SHELDUS
Lightning
Lightning occurs randomly and is, therefore, impossible to predict where it will strike. It is assumed that
all of Polk County is uniformly exposed to lightning which strikes in very small, specific geographic areas.
Impacts from lightning have included deaths and injuries, damage to electrical systems, and fires that
have destroyed residential and commercial property.
According to FEMA, an average of 300 people are injured and 80 people are killed in the United States
each year by lightning. Direct lightning strikes also have the ability to cause significant damage to
buildings, critical facilities, and infrastructure. Lightning is also responsible for igniting wildfires that can
result in widespread damages to property before firefighters have the ability to contain and suppress
the resultant fire. A discussion of the impacts to specific assets is included in the vulnerability section
(Section V).
Thunderstorms
Severe storms are localized events that can impact the whole County including residents, visitors,
transportation routes, utilities, businesses, crops and livestock. Thunderstorms can cause flooding,
property damage, and disruption of utility services such as power, telephones, or cable. Lightning
strikes can ignite wildfires or structure fires. The damages from severe storms depend on when and
where they occur and can vary based on wind and weather patterns. Generally, people are injured
during severe storm activity because of exposure to objects and debris propelled by high winds;
exposure to lightning strikes, risks associated with flash flooding and localized inundations. A discussion
of the impacts to specific assets is included in the vulnerability section (Section V).
Tornadoes
Based on historic data, tornadoes occur throughout the state of Florida at a rate of 1-10 confirmed
touchdowns per 1,000 square miles. Florida tornadoes typically impact a relatively small area; however,
events are completely random and it is not possible to predict specific areas that are more susceptible
to a tornado strike over time. Therefore, it is assumed that all of Polk County is uniformly exposed to
this hazard. April, May, and June are considered the peak months for Florida tornadoes.
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Probability of Future Occurrences
Hail
Due to the number and frequency of hail events in the County, the probability of hail events is high. The
probability for hail events is higher for Lakeland, Auburndale, Mulberry, and Winter Haven. The County
can expect to experience an average of three hail incidents per year.
Lightning
The probability of occurrence for future lightning events in Polk County is high, with an anticipated 13
lightning strikes per square kilometer per year. Polk County is part of the area referred to as the
Lightning Capital of the Western Hemisphere. Given the regular frequency of occurrence, it can be
expected that future lightning events will continue to threaten life and property throughout Polk
County.
Thunderstorms
Thunderstorms are frequent in Polk County. During the summer, Polk County experiences a
thunderstorm nearly every afternoon. They will undoubtedly continue to occur, thereby threatening the
lives, safety, and property in Polk County. Based on the historical frequency of thunderstorm events in
Polk County, the probability of future occurrences is high. The County can expect to experience a
thunderstorm event nearly every afternoon during the summer months.
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August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Figure 4.15: Severe Thunderstorms Wind Events.
The majority of severe wind events in Polk County have occurred in incorporated areas (64%). The City
of Lakeland has experienced the most events, followed by Winter Haven and Bartow.
Severe Storm Wind Events by Jurisdiction
60
50
40
30
20
10
0
Figure 4.16: Severe Storm Wind
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August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Tornadoes
According to historical records, Polk County experiences, on average, more than two (2.1) confirmed
tornado events annually. Based on the historical occurrence of tornadoes, the probability of a future
tornado affecting Polk County is high, with the County expecting to experience two confirmed tornado
events annually. While the majority of these events are small in terms of size, intensity, and duration, a
minor tornado can cause substantial damage. Tornadoes pose a significant threat to lives and property
in Polk County.
Hazard Profile – Geologic
A geologic hazard is one of several types of adverse geologic conditions capable of causing damage or
loss of property and life.
Surface Subsidence (Karst and Sinkholes)
Description and Background
Subsidence is the local downward movement of surface material with little or no horizontal movement.
According to the Florida Department of Environmental Protection (FDEP), sinkholes are closed
depressions in areas underlain by soluble rock such as limestone, dolostone, gypsum, or salt. Sinkholes
form when surface sediments subside into underground voids created by the dissolving action of
groundwater in the underlying bedrock. Other events that can cause holes, depressions, or subsidence
of the land surface that may mimic sinkhole activity include:
·
·
·
·
Subsurface expansive clay or organic layers which compress as water is removed,
Collapsed or broken sewer and drain pipes; broken septic tanks;
Improperly compacted soil after excavation work; and
Buried trash, logs, and other debris.
Sinkholes are a common feature of Florida's landscape. They are closed depressions in the land surface
formed by dissolution of near-surface rocks or by the collapse of the roofs of underground channels and
caverns. Sinkholes are a natural, common geologic feature in places underlain by soluble rocks such as
the limestone and dolomite that form the Floridan aquifer system. Sinkholes are only one of many kinds
of karst landforms, which include caves, disappearing streams, springs, and underground drainage
systems, all of which occur in Florida. Karst is a generic term which refers to the characteristic terrain
produced by erosional processes associated with the chemical weathering and dissolution of limestone
or dolomite, the two most common carbonate rocks in Florida. Dissolution of carbonate rocks begins
when they are exposed to acidic water. Most rainwater is slightly acidic and usually becomes more
acidic as it moves through decaying plant debris.
Three types of sinkholes are common in Florida: dissolution, cover-subsidence and cover collapse
sinkholes. They develop from dissolution and suffusion. Dissolution is the ultimate cause of all
sinkholes, but the type of sinkhole is also controlled by the thickness and type of overburden materials
and the local hydrology. Although it is convenient to divide sinkholes into three distinct types, sinkholes
can be a combination of types or may form in several phases.
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August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Dissolution of the limestone or dolomite is most intensive where the water first contacts the rock
surface. Aggressive dissolution also occurs where flow is focused in pre-existing openings in the rock,
such as along joints, fractures, and bedding planes, and in the zone of water-table fluctuation where
ground water is in contact with the atmosphere. Cover subsidence sinkholes tend to develop gradually
where the covering sediments are permeable and contain sand. Cover-collapse sinkholes may develop
abruptly (over a period of hours) and cause catastrophic damages. They occur where the covering
sediments contain a significant amount of clay (www.sinkholes.com).
Under natural conditions, sinkholes form slowly and expand gradually. However, activities such as
dredging, constructing reservoirs, diverting surface water, and pumping groundwater can accelerate the
rate of sinkhole expansions, resulting in the abrupt formation of collapse type sinkholes, some of which
are spectacular. In Polk County, the majority of sinkholes are attributed to drought or low water table
(75 percent).
Recorded Sinkhole Triggers
5%
6%
5%
5% 3% 1%
Drought or Low Water
Table
Unknown
Excessive Rainfall
Pumpage
Well Drilling
75%
Ground Loading
New Construction
Figure 4.17: Recorded Sinkhole Triggers; Source: Florida Geological Survey, October 2014
Sinkholes are measured in length, width, and depth, usually in feet. The largest recorded sinkhole in
Polk County was 225 long, 225 feet wide, and 50 feet deep. Another major sinkhole occurrence was 200
feet long, 200 feet wide, and 150 feet deep. Sinkholes of this extent are rare, but possible.
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August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Sinkholes 50 Feet or Deeper
22%
Bartow
4%
48%
Lake Wales
Lakeland
Mulberry
18%
4%
Winter Haven
Unincorporated
4%
Figure 4.18: Sinkholes 50 Feet or Deeper; Source: Florida Geological Survey, October 2014
Historical Occurrences
The Florida Geological Survey maintains and provides a downloadable database of reported subsidence
incidents statewide. A subsidence incident is a reported depression, which may or may not be verified
by a Licensed Professional Geologist to be a true sinkhole and the cause of the subsidence is not known.
The Subsidence Incident Report, last updated October 2014, is the source for the information for this
LMS Plan.
Subsidence incidents, including sinkholes, can happen all over the county. The majority of reported
subsidence incidents (1954 – 2014) occurred in Unincorporated Polk County (56 percent). Within the
incorporated jurisdictions, Bartow had 52 percent of the recorded incidents. Lakeland and Winter
Haven experienced 20 percent and 10 percent of the recorded incidents respectively. Davenport, Fort
Meade, Highland Park, Hillcrest Heights, and Lake Hamilton have no recorded subsidence incidents.
Subsidence Incidents by Jurisdiction
70
60
50
40
30
20
10
0
Figure 4.19: Subsidence Incidents by Jurisdiction; Source: Florida Geological Survey, October 2014
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
The most recent occurrence reported by the United States Geological Survey (USGS) of a sinkhole
occurring in Polk County was May 29, 2014 in the parking lot of Publix in the City of Winter Haven. The
sinkhole started at 30 feet in diameter but resulted in cracks extending to 140 feet across. The USGS
recorded 41 subsidence incidents in Polk County between 2000 and 2014. The USGE list is dependent
on the reporting of incidents, which means it is not a complete list of incidents. Other sinkholes occur
but are not reported to the USGS. The Red Cross responded to a sinkhole in the City of Lake Wales on
October 26, 2008.
According to the Florida Geological Survey Subsidence Incidence Reports, approximately 20% of the 278
incidents reported in Polk County since 1948 caused property damage. Table 4-15 includes a summary
of the subsidence incidents by jurisdiction.
TABLE 4-15:
SUBSIDENCE INCIDENTS BY JURISDICTION
Jurisdiction
Number of
Incidents
Comments
Auburndale
3
All under 15 feet deep; No property damage reported
Bartow
64
5 with a size of 50 feet or deeper; 1 caused property damage
Dundee
3
All in 1980s; All under 10 feet deep; one caused property damage
Eagle Lake
1
No additional information
Frostproof
1
No additional information
Haines City
2
No additional information
Lake Alfred
1
No additional information
8
1 greater than 50 feet deep; 6 cause property damage; 6 caused by
drought or low water table
Lakeland
24
4 greater than 50 feet deep; 9 caused property damage
Mulberry
2
11 greater than 50 feet deep
Polk City
1
No additional information
Winter Haven
12
11 greater than 50 feet deep
Unincorporated Polk
County
156
11 greater than 50 feet deep
6
3 incidents caused property damage; 1 incident 170 feet deep
Lake Wales
School Board
locations
Sinkholes may also be associated with phosphate mining. Please refer to the section on phosphate
mining for further discussion.
Potential Impacts
Sinkholes pose a hazard in Polk County, and throughout Florida, because they are a predominant
landform feature. Their development may be sudden. While generally not life threatening, Polk County
has experienced some property damage due to the development of this phenomenon. Additional
hazards associated with sinkholes include flooding, when the natural capacity of subsurface conduits is
exceeded, and the potential for pollutants on the land surface to move rapidly into the underlying
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
aquifer. Depending on the location of the sinkhole, severe damage can be done to individual properties
or to roads and other infrastructure. In addition to structures and infrastructure, water supplies and
environmental elements may be impacted by sinkholes. In June 2006, the 285-acre lake known as Scott
Lake abruptly drained after a sinkhole opened.
Probability of Future Occurrences
The entire county has the potential for the formation of a sinkhole. Periods of drought and heavy rain
have created suitable conditions for the formation of sinkholes. A sinkhole is likely to occur at least
once within any given year. This results in a moderate probability of a future occurrence.
Hazard Profile – Hydrologic
Hydrologic hazards are hazards driven by hydrological (i.e., water) processes.
Drought
Description and Background
A drought is a prolonged period of less than normal precipitation such that the lack of water causes a
serious hydrologic imbalance. Drought is a normal part of virtually all climatic regions, including areas
with high and low average rainfall. Drought is the consequence of a natural reduction in the amount of
precipitation expected over an extended period of time, usually a season or more in length. High
temperatures, high winds, and low humidity can exacerbate drought conditions. In addition, human
actions and demands for water resources can hasten drought-related impacts. Droughts are typically
classified into one of four types:
· Meteorological: The degree of dryness or departure of actual precipitation from an expected
average or normal amount based on monthly, seasonal, or annual time scales.
· Hydrologic: The effects of precipitation shortfalls on stream flows and reservoir, lake, and
groundwater levels.
· Agricultural: Soil moisture deficiencies relative to water demands of plant life, usually crops.
Droughts are slow-onset hazards, but over time can have very damaging affects to crops, municipal
water supplies, recreational uses, and wildlife. If droughts extend over a number of years, the direct and
indirect economic impact can be significant.
Historical Occurrences
Minor droughts occur every few years. They are usually associated with a “La Nina” event. The last
occurrence was from 1999 to 2001. According to the National Weather Service website, the most
serious event occurred in South Florida from May 2000 to May 2001. Below normal rains caused $100
million in crop damages.
·
From December 2008 - May 2009, Polk County experienced a moderate drought, while some
areas in the southwest experienced severe drought.
While a drought has not been declared for Polk County since the 2010 LMS Update, Polk County and its
jurisdictions have been on watering restrictions since the 2010 LMS Update.
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
General drought conditions were present throughout Florida in 1981, 1985, 1998-1999, and 2001. The
Keetch Bryam Drought Index is a numerical scale (0-800) that measures the amount of moisture in the
soil. A zero indicates wet, full saturation conditions while an 800 represents extreme drought
conditions. It is often used to assess the danger of wildfires but is also an indication of drought.
Therefore, it is reported where information is available.
Figure 4.20: US Drought Disaster Map June 26, 2013; Source: USDA Farm
Service Agency
Potential Impacts
Common effects of drought include crop failure, water supply shortages, and fish and wildlife mortality.
High temperatures, high winds, and low humidity can worsen drought conditions and also make areas
more susceptible to wildfire. Human demands and actions have the ability to hasten or mitigate
drought-related impacts on local communities.
Drought typically covers a large area and cannot be confined to any geographic or political boundaries.
According to the Palmer Drought Severity Index, Florida has the relatively low risk for drought hazard.
However, local areas may experience much more severe and/or frequent drought events than what is
represented on the Palmer Drought Severity Index map. Further, it is assumed that Polk County would
be uniformly exposed to drought, making the spatial extent potentially widespread. Periods of drought
can exacerbate the ignition of wildfires that can damage the natural and built environment, as has
occurred before in Polk County.
The County’s agricultural industry is at highest risk to drought. Drought can impact both crops and
livestock. In addition to the agricultural assets, droughts impact the water supply and increases wildland
fire danger and chance of sinkholes for the entire county.
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SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
Probability of Future Occurrences
It is assumed that all of Polk County is uniformly exposed to a drought event. As with any location, some
areas of the county may be affected more severely than others during a drought. Given the frequency
of previous events, warm temperatures, and average rainfall, the probability of future drought events is
moderate. As the county continues to develop with higher populations, higher water demands, and
more demands related to agriculture and livestock, these drought conditions and drier trends may begin
to have a profound impact on the county and its residents. There is a moderate chance that cycles of
reduced rains will continue to cause hydrological droughts in the future. Polk County can expect a minor
drought once every 2-3 years.
Flood
Description and Background
The National Flood Insurance Program website defines a flood as “a general and temporary condition of
partial or complete inundation of two or
more acres of normally dry land area or of
two or more properties from:
· Overflow of inland or tidal waters,
· Unusual and rapid accumulation
or runoff of surface waters from
land source, or
· A mudflow.”
The floodplain is the land adjoining the
channel of a river, stream, ocean, lake, or
other watercourse or water body that is
susceptible to flooding. Most floods fall
into the following three categories:
riverine, coastal, or shallow flooding
(where shallow flooding refers to sheet
flow, ponding, and urban drainage).
Figure 4.21: Flooded Streets in Downtown Haines City, April
30, 2014 Source: Bay News 9, Photographer: Viewer Submitted
Flooding is the most frequent and costly natural hazard in the United States, a hazard that has caused
more than 10,000 deaths since 1900. Nearly 90 percent of presidential disaster declarations result from
natural events where flooding was a major component.
Floods generally result from excessive precipitation, and can be classified under two categories: general
floods, precipitation over a given river basin for a long period of time along with storm-induced wave or
tidal action; and flash floods, the product of heavy localized precipitation in a short time period over a
given location. The severity of a flooding event is typically determined by a combination of several
major factors, including: stream and river basin topography and physiography; precipitation and
weather patterns; recent soil moisture conditions; and the degree of vegetative clearing and impervious
surface.
A general flood is usually a long-term event that may last for several days. The primary types of general
flooding include riverine, coastal, and urban flooding. Riverine flooding is a function of excessive
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precipitation levels and water runoff volumes within the watershed of a stream or river. Coastal
flooding is typically a result of storm surge, wind-driven waves and heavy rainfall produced by
hurricanes, tropical storms and other large coastal storms. Urban flooding occurs where manmade
development has obstructed the natural flow of water and decreased the ability of natural groundcover
to absorb and retain surface water runoff.
Most flash flooding is caused by slow-moving thunderstorms in a local area or by heavy rains associated
with hurricanes and tropical storms. However, flash flooding events may also occur from a dam or levee
failure within minutes or hours of heavy amounts of rainfall, or from a sudden release of water held by a
retention basin or other stormwater control facility. Although flash flooding occurs most often along
mountain streams, it is also common in urbanized areas where much of the ground is covered by
impervious surfaces.
The periodic flooding of lands adjacent to rivers, streams, and shorelines (land known as floodplain) is a
natural and inevitable occurrence that can be expected to take place based upon established recurrence
intervals. Floodplains are designated by the frequency of the flood that is large enough to cover them.
For example, 100-year floodplain by the 1 percent annual chance flood. The frequency of flood events,
such as the 1 percent annual chance flood, is determined by plotting a graph of the size of all known
floods for an area and determining how often floods of a particular size occur. Another way of
expressing the flood frequency is the chance of occurrence in a given year, which is the percentage of
the probability of flooding each year. For example, the 1 percent annual chance flood refers to area in
the 100-year floodplain and has a 1 percent chance of occurring in any given year. Similarly, the 0.2
percent flood covers the 500-year floodplain and has a 0.2 percent chance of occurring in any given
year. The recurrence interval of a flood is defined as the average time interval, in years, expected
between a flood event of a particular magnitude and an equal or larger flood. Flood magnitude
increases with increasing recurrence interval.
Many areas of Polk County are susceptible to riverine and urban (stormwater) flooding. Figure 4.22 (and
map in Appendix A) illustrates the location and extent of currently mapped Special Flood Hazard Areas
for Polk County based on best available FEMA Digital Flood Insurance Rate Map (DFIRM) data. This
includes Zones A/AE (100-year floodplain), Zone VE (100-year coastal flood zones, associated with wave
action), and Zone X (500-year floodplain). It is important to note that while FEMA digital flood data is
recognized as best available data for planning purposes, it does not always reflect the most accurate and
up-to-date flood risk. The Southwest Florida Water Management District is currently in the process of
updating the Flood Insurance Rate Maps for Polk County, so the spatial extent of the floodplain may
change.
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Figure 4.22: FEMA Flood Insurance Rate Map Source: FEMA and Polk County
Historical Occurrences
July 1, 2005
June rainfall of 14 to 18 inches in eastern Polk County had increased
lake water levels from Lake Wales to Frostproof. The water levels were
already high after three hurricanes moved over the area in 2004. Some
lake levels rose 10 feet in a 12-month period. About 107 manufactured
homes were lost to the flooding. About 175 of the 700 homes at
Saddlebag Lake were surrounded by water. The county performed
pumping operations in an attempt to lower lake levels. There are no
natural outlets for most of the lakes in eastern Polk County. The
damage estimates for this event were approximately $1.6 million.
April 6, 2008
Flooding occurred due to heavy rainfall in Auburndale, Bartow,
Lakeland, and Haines City. Total property damage was about $50,000.
August 20, 2008
Flooding occurred due to heavy rainfall in the Frostproof area. Seven
homes received up to 3 feet of water and total property damage was
about $250,000.
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According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1960 through 2012, 25
flooding events occurred. They resulted in one injury, approximately $3.5 million in crop damages, and
approximately $8.4 million in property damages. Table 4-16 includes the flooding incidents from 2000 –
2014 as reported by National Climactic Data Center.
TABLE 4-16:
FLOOD INCIDENTS BY LOCATION
Date
Location
Type
Deaths
Injuries
07/21/2000
Ft Meade
Flash Flood
0
0
$50,000
$0
08/25/2000
Haines City
Flood
0
0
$25,000
$0
09/17/2000
Bartow
Flash Flood
0
0
$25,000
$0
06/24/2002
Lakeland
Flash Flood
0
0
$0
$0
06/30/2002
Ft Meade
Flood
0
0
$0
$0
09/04/2002
Lakeland
Flood
0
0
$0
$0
10/23/2002
Mulberry
Flood
0
0
$0
$0
12/13/2002
Lakeland
Flood
0
0
$0
$0
12/24/2002
Lakeland
Flash Flood
0
0
$150,000
$0
12/31/2002
South Portion
Flash Flood
0
0
$90,000
$0
01/01/2003
Polk County
Flood
0
0
$0
$0
06/24/2003
Polk County
Flood
0
0
$0
$0
09/06/2004
Polk County
Flood
0
0
$0
$0
09/26/2004
Lakeland
Flash Flood
0
0
$350,000
$0
07/01/2005
Polk County
Flood
0
0
$1,600,000
$0
04/06/2008
Jack Brown’s Seaport
(Lake Alfred)
Flash Flood
0
0
$50,000
$0
08/20/2008
Frostproof Airport
(Frostproof)
Flood
0
0
$250,000
$0
Source:
Property
Damage
Crop Damage
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Historical Summary of Insured Flood Losses
All jurisdictions in Polk County except the Town of Hillcrest Heights and the Village of Highland Park
participate in the National Flood Insurance Program (NFIP). According to FEMA flood insurance policy
records as of August 2013, there have been 758 flood losses reported in Polk County, totaling
approximately $8.1 million in claims payments. Table 3-4 (Section III) provides flood insurance policy
and claim summary information for each of the participating jurisdictions. It should be emphasized that
these numbers include only those losses to structures that were insured through the NFIP policies, and
for losses in which claims were sought and received. It is likely that additional instances of flood losses
in Polk County were either uninsured, denied claims payment, or not reported.
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Repetitive Loss Properties
FEMA defines a repetitive loss property as any insurable building for which two or more claims of more
than $1,000 were paid by the NFIP within any rolling 10-year period, since 1978. A repetitive loss
property may or may not be currently insured by the NFIP. Currently, there are over 122,000 repetitive
loss properties nationwide.
According to FEMA repetitive loss property records (as of April 2009), there are 27 “non-mitigated”
repetitive loss areas in Polk County based on topography (see Repetitive Loss Activity Map in Appendix
A). These 27 properties are all located in unincorporated Polk County. Without mitigation, these
properties will likely continue to experience flood losses. Since the 2010 LMS document, seven
repetitive loss properties were removed through either property buy-out or demolition. The last
repetitive loss property located in the City of Lakeland was demolished in 2008 and therefore, removed
from the list. Table 4-17 provides summary information about repetitive loss properties in Polk County.
TABLE 4-17
REPETITIVE LOSS PROPERTIES
Type of Use
Number of
Properties
Residential
Location
24
Unincorporated Polk County
Commercial (Office and Club/Lodge)
2
Unincorporated Polk County
Industrial (Light Manufacturing)
1
Unincorporated Polk County
27
Unincorporated Polk County
Total
Source:
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Polk County is currently in the process of updating their Community Rating System (CRS) requirements
based on the 2013 CRS manual as part of the 5-year cycle visit scheduled for October 2015. Polk County
reviews and updates the list of repetitive loss properties, describes the causes of the losses, and
coordinates outreach to those areas each year.
Potential Impacts
Floods can have devastating consequences and can have effects on the economy, environment,
structures, and people. During floods, especially flash floods, roads, bridges, farms, houses, and
automobiles may be destroyed. People become homeless and water supply and electricity are
disrupted causing people to struggle and suffer. Additionally, the government deploys firemen, police,
and other emergency apparatuses to help the affected. All these come at a heavy cost to people and
the government. It usually takes years for affected communities to be re-built and business to come
back to normalcy. Chemicals and other hazardous substances end up in the water and may contaminate
the water bodies into which they flow. Additionally, flooding kills animals, and insects are introduced to
affected areas, distorting the natural balance of the ecosystem.
Probability of Future Occurrences
There is a long history of flooding in Polk County and most of central Florida. This trend is expected to
continue with some type of flooding event expected to occur on average once a year. There is a
moderate probability of heavy flooding occurring. The probability of future flood events based on
magnitude and according to best available data is illustrated in Figure 4.21 and Appendix A, which
indicates those areas susceptible to the 1 percent annual chance flood (100-year floodplain); the 1
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percent annual chance flood with wave action (100-year coastal floodplain); and the 0.2 percent annual
chance flood (500-year floodplain).
Hazard Profile – Other Natural Hazards
Other Natural Hazards refer to natural hazards that are not atmospheric, geological, or hydrologic.
Climate Change
Description and Background
According to the Environmental Protection Agency (EPA), climate change refers to any significant change
in the measures of climate lasting for an extended period of time. Climate change includes major
changes in temperature, precipitation, or wind patterns, among other effects, that occur over several
decades or longer. Earth's average temperature has risen by 1.4°F over the past century, and is
projected to rise another 2°F to 11.5°F over the next hundred years. Small changes in the average
temperature of the planet can translate to large shifts in climate and weather. This hazard occurs at a
regional geographic level; therefore, the entire county is likely to be uniformly exposed to climate
change.
Historical Occurrences
No specific events have been reported since the 2010 LMS update. Figure 4.22 illustrates the historic
and projected average annual temperatures for the Bartow, Florida temperature station. Historical data
from the Global Historical Climatology Network (GHCN) is illustrated in gray. As illustrated in the Figure,
the temperature at the Bartow measurement station has increased between 1900 and 2000.
Figure 4.23: Historic and Projected Temperature Change in Bartow; Source: www.wunderground.com
Potential Impacts
According to the EPA, rising global temperatures have been accompanied by changes in weather and
climate. Many places have seen changes in rainfall, resulting in more floods, droughts, or intense rain,
as well as more frequent and severe heat waves. The planet's oceans and glaciers have also
experienced some big changes - oceans are warming and becoming more acidic, ice caps are melting,
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and sea levels are rising. As these and other changes are forecast to be more pronounced in the coming
decades, they will likely present challenges to our society and our environment. Climate change has the
potential to impact food supply, water resources, infrastructure, ecosystems, and health. In recent
years, scientists have observed changes in Florida that they believe to be consistent with the impacts of
climate change. These changes include retreating and eroding shorelines, dying coral reefs, salt-water
intrusion into the freshwater aquifer, increasing numbers of forest fires, and warmer air and sea surface
temperatures. The most likely impacts to centrally located Polk County may include fresh water
supplies, human health, agriculture, natural ecosystems, and hurricanes.
Potential salt-water intrusion into the Floridan aquifer could limit the supply of fresh water to Polk
County. The economic, agricultural and health impacts of such a limitation of fresh water supply are
difficult to predict. Increases in average temperature are also predicted to have an impact on the
severity and frequency of severe storms, including hurricanes, and droughts. Again, the specific impacts
to Polk County are difficult to predict. Much of the impact would be dependent upon our ability to
adapt, using technology and other innovations to protect against such storms and droughts.
As illustrated in Figure 4.23, the projected average annual temperatures for the Bartow, Florida
temperature station will increase over time. Heat waves are expected to increase between 97 percent
and 234 percent by the end of the century. High temperature stresses in the summer will become more
frequent and damaging to agriculture, possibly moving dairy and livestock production farther north and
reducing yields of citrus, blueberries, peaches, and other crops. Climate change will affect every aspect
of water resource management, including water quantity and quality, natural systems protection, flood
protection, and drought management. The Regional Water Supply Plan for Polk County will address
these changes.
Probability of Future Occurrences
The EPA predicts future changes in temperatures, precipitation, and storm events. The magnitude and
rate of future climate change depends on several factors. The probability of future occurrences for Polk
County is moderate, based on the historical occurrences of increased temperatures and the projected
changes in temperatures and the impacts they can cause. The County can expect to experience an event
tied to climate change in the next ten years.
Wildfire
Description and Background
The Florida Forest Service (FFS) defines wildfire as any fire that does not meet management objectives
or is out of control. Wildfires occur in Florida every year and are part of the natural cycle of our fireadapted ecosystems. Many of these fires are quickly suppressed before they can damage property.
Prescribed or controlled fires have been used to replace the natural benefits that wildfires provide on
many conservation and ranch properties across the state. Despite the advancements of fire
management across the state, many large and destructive wildfires still occur during severe droughts.
Nationally, over 80 percent of forest fires are started by negligent human behavior such as smoking in
wooded areas or improperly extinguishing campfires. The second most common cause for wildfire is
lightning.
According to the State of Florida Enhanced Mitigation Plan, there are four types of wildfires:
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·
Surface Fires: Burn along the forest floor consuming the litter layer and small branches on or
near the ground.
·
Ground Fires: Smolder or creep slowly underground. These fires usually occur during periods of
prolonged drought and may burn for weeks or months until sufficient rainfall extinguishes the
fire, or it runs out of fuel.
·
Crown Fires: Spread rapidly by the wind, moving through the tops of the trees.
·
Wildland/Urban Interface (WUI) Fires: Fires occurring within the WUI in areas where structures
and other human developments meet or intermingle with wildlands or vegetative fuels. Homes
and other flammable structures can become fuel for WUI fires.
Prescribed or controlled fires have been used on both public and private lands across the state to
replace the natural benefits that wildfires can provide. Prescribed burns help to reduce the amount of
flammable vegetation in an area, which in turn lessens the intensity of a wildfire that may occur in that
same area. Firefighters then have an opportunity to suppress the fire while it is small and easier to
control. Humans cause approximately 70 percent to 80 percent of all wildfires in Florida.
Florida Wildfire Causes
7% 1%
1%1% 0%
Lightning
9%
35%
10%
Incendiary
Unknown
Equipment Use
Debris Burn
Miscellaneous
Campfire
13%
Smoking
23%
Children
Figure 4.24: Florida Wildfire Causes
The type and amount of fuel, as well as its burning qualities and level of moisture, affect wildfire
potential and behavior. The continuity of fuels, expressed in both horizontal and vertical components, is
also a factor because it expresses the pattern of vegetative growth and open areas. Topography is
important because it affects the movement of air (and thus the fire) over the ground surface. The slope
and shape of terrain can change the rate of speed at which the fire travels. Temperature, humidity, and
wind (both short- and long-term) affect the severity and duration of wildfires.
Polk County is a large interior County with a great deal of rural landscape in the form of agricultural and
conservation lands, therefore, wildfires have the ability to affect all jurisdictions within Polk County.
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Historical Occurrences
According to the Polk County Community Wildfire Protection Plan (2011), in the past 30 years there
have been 263,439 acres burned from wildfires in Polk County. A majority of the fires have been
relatively small in size, under 10 acres. This amount does not include brush fires that were suppressed
by local firefighters without Florida Department of Forestry (FDOF) assistance. Polk County Fire Rescue
also keeps statistics on brush fires. Between July 1981, and June 2011, Polk County experienced over
7,000 fires.
The Florida Forest Service includes one fire in Polk County on its Significant Wildfires in Florida 19812008 list, which is described below:
February 15, 2001
The Stagecoach Fire burned approximately 11,000 acres of mainly grass, scrub
trees and shrubs along and north of the Interstate 4 corridor over mainly rural
portions of northern Polk County. Approximately 17 miles of Interstate-4
between Polk City and Lakeland were closed for almost ten days due to
billowing smoke, burned fence posts that allowed cattle on the road, and zero
visibility. A trash fire is believed to be the cause of the wildfire. The variable
smoke plume produced by the wildfire occasionally reduced visibility to
between one half and two miles as far west as St. Petersburg in Pinellas County.
Also, ash from the smoke plume was deposited as far southwest as Ft. Myers in
Lee county of Southwest Florida.
According to the Spatial Hazard Events and Losses Database (SHELDUS), from 1998 through 2012, 5
wildfire events occurred. They resulted in five injuries and approximately $4.5 million in property
damages. Table 4-18 includes the wildfire incidents from 2000 – 2014 as reported by National Climactic
Data Center.
TABLE 4-18:
WILDFIRE INCIDENTS BY JURISDICTION
Date
Jurisdiction
Death
Injuries
3/14/2000
Mulberry
0
0
$75,000
$0
4/8/2000
Ft. Meade
0
0
$0
$0
4/11/2000
Mulberry
0
0
$0
$0
2/18/2001
Polk City
0
0
$0
$0
5/23/2001
Polk County
0
0
$0
$0
Polk County
0
0
$150,000
$0
3/2/2007
Source:
Property
Damage
Crop Damage
National Oceanic and Atmospheric Association; www.ncdc.noaa.gov
Since 2010, there have been no major wildfire incidents that threatened Polk County. According to the
Lakeland Ledger, on May 20, 2015, two separate fires occurred north of Lakeland. The first was a twoacre muck fire that was believed to have been started with illegal burning. The second was a three-acre
brush fire. No structures were reported to be in danger and no injuries were reported.
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Potential Impacts
Many individual homes and cabins, subdivisions, resorts, recreational areas, organizational camps,
businesses, and industries are located within high wildfire hazard areas. Further, the increasing demand
for outdoor recreation places more people in wildlands during holidays, weekends, and vacation
periods. Wildfires can result in severe economic losses as well. Businesses that depend on timber, such
as paper mills and lumber companies, experience losses that are often passed along to consumers
through higher prices. In cases, this has resulted in the loss of jobs. The high cost of responding to and
recovering from wildfires can deplete state resources and increase insurance rates. The economic
impact of wildfires can also be felt in the tourism industry if roads and tourist attractions are closed due
to health and safety concerns.
Probability of Future Occurrences
Wildfire probability depends on local weather conditions, outdoor activities such as camping, debris
burning, and construction, and the degree of public cooperation with fire prevention measures.
Drought conditions and other natural hazards (such as tornadoes, hurricanes, etc.) increase the
probability of wildfires by producing fuel in both urban and rural settings. Forest damage from
hurricanes and tornadoes may also block interior access roads and firebreaks, pull down overhead
power lines, or damage pavement and underground utilities. There is a high probability of future
wildfire events in Polk County, especially during drought cycles and abnormally dry conditions, based on
prior occurrence.
Controlled/prescribed burns are an effort to control outbreaks of wildfires by burning the underbrush,
which would contribute significantly to fueling flames. Because of these regularly scheduled burns, the
likelihood of a major wildfire is normally low to moderate, which is about one event every four to five
years. During periods of drought, the probability increases from moderate to high, which is about one
event every year. See Appendix A.
Hazard Profile – Man-Made Hazards
Man-made hazards can result in the form of a man-made disaster.
In this case, it means threats having an element of human intent,
negligence, or error; or involving a failure of a human-made system.
This is as opposed to natural hazards that cause natural disasters.
Dam/Levee Failure
Description and Background
A dam is a barrier constructed to hold back water and raise its level
while a levee is a structure designed to prevent or control a flood.
The terms are used interchangeably in this report. The National
Inventory of Dams defines any "major dam" as being 50 feet (15 m)
tall with a storage capacity of at least 5,000 acre feet (6,200,000
m3), or of any height with a storage capacity of 25,000 acre feet
(31,000,000 m3). Water control structures help provide flood
protection, manage lake water levels, and prevent salt water from
flowing up freshwater streams and creeks. When the term “dam” is
used, it is normal to think only of structures associated with the
impounding of rivers for use as drinking water reservoirs, the
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Figure 4.25: Chain of Lakes Lock
System; Source: worldbarefootcenter.com
August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
production of electricity, or flood control. In Florida, the term can take on an additional meaning, that
of impounding clay settling ponds or phosphogypsum stacks associated with the mining and processing
of phosphate. Both types of dams can be found within Polk County.
According to FEMA, dams can fail for one or a combination of the following reasons:
· Overtopping caused by floods that exceed the capacity of the dam
· Deliberate acts of sabotage
· Structural failure of materials used in dam construction
· Movement and/or failure of the foundation supporting the dam
· Settlement and cracking of concrete or embankment dams
· Piping and internal erosion of soil in embankment dams
· Inadequate maintenance and upkeep
A flood event may also trigger a dam/levee failure. The dam impounds water in the reservoir, or
upstream area. The amount of water impounded is measured in acre-feet. Dam failures are not routine
but the results can be significant. Two factors influence the potential severity of a dam failure: (1) the
amount of water impounded and (2) the density, type, and value of the development downstream
(Statewide Hazard Mitigation Plan, 2009).
The “dam hazard” is a term indicating the potential hazard to the downstream area resulting from
failure or mis-operation of the dam or facilities. According to the USACE National Inventory of Dams,
there are 261 dams in Polk County, which have been identified by their hazard risk of low, significant,
and high.
·
Low hazard: A dam where failure or mis-operation results in no probable loss of human life and
low economic and/or environmental loss. Losses are principally limited to the owner’s property.
·
Significant hazard: A dam where failure or mis-operation results in no probable loss of human
life but can cause economic loss, environmental damage, disruption of lifeline facilities or
impact other concerns. These dams are often located in predominantly rural or agricultural area
but could be located in areas with population and significant infrastructure.
·
High hazard: A dam where failure or mis-operation will probably cause loss of human life.
Water control structures and dams are located throughout Polk County. According to the State of
Florida Enhanced Hazard Mitigation Plan, Polk County has the largest number of dams in the state.
Figure 4.27 illustrates the general locations of structures in Polk County identified through the National
Inventory of Dams. The majority of the structures identified in Polk County are located in the southwest
portion of the County, with some in the northeast and along the Kissimmee River in the southwest
portion. More detailed location information is not included in the LMS document to meet requirements
of the U.S. Army Corps of Engineers National Inventory of Dams non-disclosure agreement. Mining
operations that have dams in Polk County are located in the southwestern portion of the county. The
following list is compiled from several resources.
·
Lake Hartridge Dam is on the Lake Conine River in Polk County, Florida and is used for recreation
purposes. Construction was completed in 1959. It is owned by W H L R Boat Course. Lake
Hartridge Dam is of earthen construction. Its length is 40 feet. Maximum discharge is 121 cubic
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feet per second.
(Findlakes.com).
Its capacity is 29,946 acre feet.
Normal storage is 29,946 acre feet
·
Kissimmee River Basin: Two water-control structures (S-65 and S-65A) are located on the border
of Polk County. These structures historically were managed to maintain a constant water level
in the navigation pools of the Kissimmee River (Hydrology of Polk County).
·
Lake Water Level Controls: Forty-two of the 262 named lakes (16 percent) in Polk County
inventoried by Gant (2001) were reported to have a control structure on the outlet. The
Southwest Florida Water Management District maintain thirteen water control structures in
Polk County.
o The Winter Haven Chain of Lakes consists of 13 interconnected lakes—Lake Mariana,
Lake Jessie, Lake Idylwild, Lake Hartridge, Lake Cannon, Lake Mirror, Lake Deer, Lake
Howard, Lake May, Lake Shipp, Lake Eloise, Lake Winterset, and Lake Lulu. An outlet
structure on Lake Lulu regulates the water levels in the lakes.
o Lakes Hartridge and Conine are connected by a canal. Locks in the canal permit the flow
of water from Lake Hartridge to Conine during high water levels (U.S. Environmental
Protection Agency, 2005).
o The Banana Lake Water Conservation Structure is located southeast of Lakeland, on the
northeastern shore of Banana Lake, just east of US 98. The structure’s manually
operated gates were constructed in 1969 to help maintain water levels on the lake.
o The Circle B Center Water Conservation and Drainage Structure is located east of
Lakeland on the District’s Circle B Bar Reserve property. Along with the Circle B East
structure, the Circle B Center structure’s gates can be manually operated to help control
the flow of water from Banana Lake and area wetlands into Lake Hancock.
o The Circle B East Water Conservation and Drainage Structure is located east of
Lakeland, on the District’s Circle B Bar Reserve property. Along with the Circle B Center
structure, the Circle B East structure’s gates can be manually operated to help control
the flow of water from Banana Lake and area wetlands into Lake Hancock.
o The Lake Gibson Water Conservation Structure is located in Lakeland off North Socrum
Loop Road near Lake Gibson’s southeast side. The structure’s gates can be remotely
operated to help maintain water levels on the lake.
o The P-1 (Lake Lena) Water Conservation Structure is located in Auburndale at the south
end of Lake Lena, just off US 92. The structure’s gate can be manually operated to help
maintain water levels on Lake Lena.
o The P-3 (Lake Arietta) Water Conservation Structure is located northwest of
Auburndale near the northeast shore of Whistler Lake, just off Kirkland Lake Drive. The
structure’s gate can be remotely operated to help maintain water levels on Lake Arietta.
o The P-5 (Lake Henry) Water Conservation Structure is located in Winter Haven, south of
SR 544 and west of US 27. The structure’s gate can be manually operated to help
maintain water levels in Lake Henry.
o The P-6 (Lake Smart) Water Conservation Structure is located in Winter Haven, south of
SR 544, between Lake Smart and Lake Fannie. The structure’s gate can be manually
operated to provide flood protection and to help maintain water levels in the Winter
Haven chain of lakes.
o The P-7 (Lake Fannie) Water Conservation Structure is located in Winter Haven,
between Lake Fannie and Lake Hamilton. The structure’s gates can be manually
operated to help maintain water levels in Lake Fannie.
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o
o
o
o
·
The P-8 (Lake Hamilton) Water Conservation Structure is located north of Winter
Haven on the southern outfall canal for Lake Hamilton, off Crump Road. The structure’s
gates can be manually operated to help maintain water levels in Lake Hamilton.
The P-11 (Lake Hancock) Water Conservation Structure is located in Bartow on Saddle
Creek just east of US 98. The structure’s gates can be manually operated to help
maintain water levels in Lake Hancock.
The Lake Parker Water Conservation Structure is located in Lakeland on the east side of
Lake Parker, just off East Lake Parker Drive. The structure’s gate can be manually
operated to help maintain water levels in Lake Parker.
The Scott Lake Water Conservation Structure is located south of Lakeland on Scott Lake
Road, south of Lake Miriam Drive. The structures stop logs can be added or removed to
help maintain water levels on Scott Lake, although a sinkhole drained the lake in 2006.
Phosphate mining over the years has moved through Lakeland, Mulberry, Bartow, and Plant
City. In the past 15 years, however, mining operations on Polk County’s southern fringe has
wound down. The closing of the IMC Clear Springs and Noralyn mines in 2000 has signaled a
close to active mining in what has been the heart of the mining district since the mining of
phosphate pebble on land began in the late 1800s (Florida Industrial and Phosphate Research
Institute).
Figure 4.26: Major Surface-water Drainage Basins, Tributaries, and Lakes
Source: Hydrology of Polk County, US Geological Survey, 2007
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Figure 4.27: Polk County Dam Location Map; Source: USACE, National Inventory of Dams
http://nid.usace.army.mil/cm_apex/f?p=838:7:0::NOgeo.usace.army.mil
Historical Occurrences
Since 2010, there have been no recorded instances of dam/levee failure or breech in Polk County. Many
dam/levee failures are related to the clay setting ponds and gypsum stacks associated with phosphate
mining. Please refer to the section on phosphate mining for a detailed discussion.
Probability of Future Occurrences
Section 62-672 Florida Administrative Code and Section 373, Florida Statutes, govern the construction
and safety of dams and levees in Florida. According to FDEP, dam inspections in Florida are conducted
by agency personnel at the state, regional, and local levels, as related to their respective regulatory
programs, as well as by private dam owners. Oversight for phosphate mining and similar industrial
impoundments is primarily the responsibility of the FDEP. Other dams generally fall within the purview
of the USACE, the State’s five regional water management districts, or local government agencies.
The probability that future dam and levee failures will occur somewhere within the planning area is low
based on historical data; however, such an occurrence cannot be excluded. Based on the available
information for historical occurrences profiled in this section and the phosphate mining section, the
county has experienced a 13 percent annual hazard risk (6 incidents in 47 years). While this is a very low
occurrence, the number of dams/levees that are over 50 years of age and the number of structures
ranked as significant or high downstream hazard potential increases the county’s risk from very low to
low. The majority of dams categorized as having a high downstream hazard potential are remnant
mining ponds that have dried up. Based on the conditions of these structures and the history of dam
failures in the county, the county can expect to experience one dam failure every ten years. The State of
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Florida Enhanced Hazard Mitigation Plan identifies Polk County as having a high and significant hazard
for dam failure.
The closing of processing plants has raised concerns regarding the maintenance of the phosphogysum
stacks. Of particular concern is the capacity of the stack being exceeded following major or longduration rainfall events. Per the Florida Department of Environmental Protection (FDEP) upon
completion of closure activities the owner takes over long-term care responsibilities as portions of the
stack system are closed.
Epidemics
Description and Background
An epidemic is a rapid spread or increase in the occurrence of something. Epidemics frequently refer to
infectious diseases, but also include agricultural diseases and exotic pests, and social activities such as
drug use.
·
Infectious Disease
Infectious diseases are illnesses caused by the presence and activity of one or more pathogenic
agents including viruses, bacteria, fungi, protozoa, multicellular parasites and abnormal proteins
called prions. They are transmitted through a variety of means including direct or indirect
contact; ingestion (in water or food); transmission of body fluids; inhalation of airborne particles
and droplets; transmission by vectors such as mosquitoes, fleas, and ticks; and others.
·
Exotic Pests and Diseases
Two of the major industries in Polk County for many years have been citrus production and
cattle ranching. In the past, several pests and diseases have threatened the citrus population
(Mediterranean fruit fly (1997) and citrus canker (2005–06). The large animal population (cattle,
horses, etc.) were threatened in 1992 by eastern equine encephalitis. Citrus Greening and black
spot are diseases that are impacting the citrus industry and continuing to spread through Polk
County. Figure 4.26 illustrates the locations in 2014 of citrus Greening in relation to commercial
citrus production areas.
·
Social Activities
Social activities, such as drug use, can reach epidemic proportions. As the “Pill Mill Capital of
the United States”, Polk County had a prescription narcotic abuse problem. Polk County was
also referred to as the “Meth Capital of the World.” (see Articles in Appendix G).
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Figure 4.28: Citrus Greening Location Map; Source: Citrus Health Response Program
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The spread of infectious disease depends upon pre-existing levels of the disease, ecological changes
resulting from disaster, population displacement, changes in density of population, disruption of public
utilities, interruption of basic public health services, and compromises to sanitation and hygiene. The
risk that epidemics of infectious disease will occur is proportional to the population density and
displacement. A true epidemic can occur in susceptible populations in the presence or impending
introduction of a disease agent compounded by the presence of a mechanism that facilitates large-scale
transmission.
Historical Occurrences
According to the Florida Department of Health, Florida has been heavily impacted by the HIV/AIDS
epidemic. The state continues to rank third in the nation in the cumulative number of AIDS cases
(126,581 in 2012) and second in the nation in the cumulative number of HIV cases (49,058 in 2012). The
Florida Department of Health estimates that approximately 130,000 individuals are living with HIV
disease in Florida. Of those persons living with HIV disease, 49% are black, 29% are white and 20% are
Hispanic. Men represent 70% of the cases. Persons over the age of 45 years represent 60%.
Since 2000, Polk County has experienced a dramatic increase in the manufacture, sale, and use of
methamphetamines. The County is considered by local and regional law enforcement agencies to be a
major center of production and traffic in illegal drugs. This has resulted in a corresponding increase in
the incidence of Hepatitis A and resulted in several deaths. Beginning in 2002, the Polk County Health
Department initiated an aggressive program to control the disease. It is currently considered to be
under control.
During 2001 and 2002 an outbreak of Arbovirus diseases was experienced throughout the State. Polk
County was included in a Department of Health Special Alert for mosquito borne illnesses including East
Equine Encephalitis, West Nile Virus, and St. Louis Encephalitis. The Special Alert remained in effect
until January 2003. During the period of the alert, there were several illnesses and one death in the
State.
In 2015, two potentially fatal mosquito-borne infectious diseases broke out in the Caribbean: Dengue
Hemorrhagic Fever and Chikungunya Fever. To date, eleven people in Florida have become sick. The
state is investigating the option of releasing a genetically modified mosquito into the Florida Keys to
potentially combat the spread of infected mosquitoes.
Potential Impacts
Epidemics have an overwhelming impact on a population both directly and indirectly. This cost
encompasses hospitalizations, insurance premiums, outpatient visits, and even death. The spread of
exotic species and diseases may cause a change in the local flora/fauna and have impacts on the
economy – such as a change in agricultural crops. Social epidemics such as drug use impact social,
economic, and political aspects of the community.
Probability of Future Occurrences
According to the University of Florida IFAS extension, some emerging infectious diseases (EIDs) such as
AIDS, antibiotic resistant bacteria, tuberculosis, and others are already a threat to Florida and the United
States. Others, such as dengue and dengue hemorrhagic fever, pose a credible threat to certain areas of
the continental United States such as Florida and Texas, and have had outbreaks in Hawaii and Puerto
Rico. Another group of EIDs may present a hazard only to travelers visiting or working in foreign
locations where these diseases are endemic. Finally, the use of disease organisms such as Bacillus
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anthracis (anthrax), Francisella tularensis (tularemia), smallpox and ebola viruses, and others in
bioterrorist attacks is now a real threat in many countries including the United States.
The probability of future occurrences as a whole is even across Polk County. Areas of the county with
high concentrations of agricultural production have a higher level of exposure for impacts of citrus
greening and other agricultural pests and diseases.
Hazardous Materials Incidents
Description and Background
Hazardous Materials (HazMat) refers generally to hazardous substances, petroleum, natural gas,
synthetic gas, and acutely toxic chemicals. The term Extremely Hazardous Substance (EHS) is used in
Title III of the Superfund Amendments and Reauthorization Act of 1986 to refer to those chemicals that
could cause serious health effects following short-term exposure from accidental releases.
SQG – Small Quantity Generator of Hazardous Waste are facilities that generate hazardous waste as a
product or a byproduct of their normal business function. These facilities are inspected. Classic
examples of SQGs would include:
· Auto Paint & Body Shops (paints and solvents, anti-freeze)
· Doctor/Dentist offices that still use wet read x-rays versus digital (photographic silver)
· Auto mechanic shops (oils, solvents, anti-freeze)
· Pesticide waste (plastic containers)
· Florescent light tubes (mercury)
302 sites – Facilities that use/consume extremely hazardous substances (EHS) in the normal process of
their business. Generally, there will be large amounts of these substances stored on site and used as
needed. An EHS is a substance that has the potential to kill or cause serious health issues to a person.
Some of the classic examples of EHS include:
· Chemicals that are used in the groves (paraquat dichloride, temmic)
· Large battery back-up systems for telephone communications (sulfuric acid & lead)
· Manual blood pressure cuffs (mercury)
· Refrigerants (anhydrous ammonia)
· Chlorine – vs – Sodium Hypochlorite, used for water purification
Since 1989, Polk County has been ranked either first or second in the state in the number of facilities
which use, store, manufacture or transport chemicals that have been designated by the Environmental
Protection Agency (EPA) as Extremely Hazardous Substances (EHS). The total number of facilities in Polk
County varies from year to year due to a variety of factors. Since 1992, the numbers of facilities
required to file reports on EHSs on site has ranged between 200 and 350. The potential for incidents
involving these substances is high.
Of the numerous hazardous materials incidents reported statewide each year, less than one percent
resulted in fatalities, less than four percent resulted in injuries, and less than six percent resulted in
evacuation. Hazardous materials incidents can occur anywhere there is a road, rail line, or fixed facility
storing hazardous materials. Virtually the entire county is a risk to an unpredictable incident of some
type. Most incidents are small and confined to a relatively localized area.
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In Polk County, sulphuric acid is the EHS that is found in the greatest volume. This substance is used in
conjunction with mining operations and fertilizer production. The facilities using sulphuric acid in large
quantities are concentrated in the southwest section of the county.
TABLE 4-19:
AMOUNT OF CHEMICALS BY SITE IN COUNTY
Chemical
EHS
Number of
Sites
Total
Amount
High Sulpher Diesel
No
180
45,401,263
Sulphuric Acid
Yes
127
78,584,024
Chlorine
Yes
64
Gasoline
No
Ammonia/Anhydrous
Ammonia
Low
Average
17,074,521
300
252,229.23
27,110,000
578
618,771.80
667,130
450,000
150
10,580.0
61
4,151,870
999,999
186
84,292.95
Yes
45
4,119,836
1,376,000
600
91,551.91
Sodium Hypochlorite
No
42
2,001,682
386,400
200
47,659.10
Lead
Yes
35
2,875,072
664,160
4,060
82,144.91
Propane
No
26
1,816,247
407,040
440
69,885.70
Sodium Hydroxide
No
25
3,168,801
964,000
12,000
126,752.00
Hydrotreated Heavy
Paraffinic Petroleum
Distallates
No
19
856,766
538,116
1,152
45,092.00
Source:
High
Polk County
Hazardous material incidents can occur during
production, storage, transportation, use, or disposal.
Communities are at risk if a chemical is used unsafely
or released in harmful amounts into the environment.
Polk County and its jurisdictions participate in the
District 7 Local Emergency Planning Committee (LEPC)
whose responsibilities include collecting information
about hazardous materials in the community and
making this information available to the public upon
request. The LEPC is also tasked with developing an
emergency plan to prepare for and respond to
chemical emergencies in the community. Ways the
public will be notified and actions the public must
take in the event of a release are part of the plan.
Historical Occurrences
Figure 4.29: View of a phosphogypsum stack.
Source: www.fluoridealert.org
Between 2010 and 2015, there have been 41 hazardous material incidents in which the incident was
fully contained on-site and no evacuation was required. No injuries were reported for any of the 41
incidents.
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Between 2010 and 2015, there were 13 hazardous materials incidents in which there were off-site
impacts and/or evacuation and injuries. Those incidents are listed below.
September 27, 2011
Haines City Citrus Growers, Anhydrous Ammonia Release did not go off
site. Thirty people were evacuated. There were no injuries.
January 25, 2011
Cutrale Citrus Auburndale, Anhydrous Ammonia Release did not go off
site. One employee was taken to the local hospital and was treated and
released.
February 21, 2012*
Vehicular accident resulted in a spill of 125 gallons of sulfuric acid. The
spill was contained at the site of the accident and there was no
evacuation.
March 7, 2012
CSX Railroad Train and fuel tanker truck collision, 3,000 gallons of diesel
released and burned causing a wildfire, driver of truck was killed, SR 60
was closed for an extended period of time. The accident occurred on
Mosaic property west of Bartow.
April 24, 2012*
A vehicular accident resulting in the release of 1,000 gallons of sulfuric
acid. There was no evacuation other than to seal off the area where the
spill occurred. The driver of the truck was injured and evacuated from
the site.
June 5, 2012*
There was an accident where a forklift punctured a drum of sulfuric
acid. This did not go offsite or cause an evacuation. The forklift driver
was injured and evacuated for treatment.
September 29, 2012
There was an off-site release of Anhydrous Ammonia resulting in an
evacuation of 25 people from the Florida Brewery in Auberndale. There
were no injuries.
NOTE: all three of the releases marked with an * involved Davis Supply
Company.
November 16, 2013
Dundee Citrus Packing House, Anhydrous Ammonia leak with
evacuations. The release did not go offsite. There were no injuries
reported.
October 28, 2013
Taste Advantage Chemical Release with minor injuries. Acetic Acid was
released. It did not go off site. There was an evacuation ordered until
the situation was brought under control. One employee suffered a
minor injury.
January 8, 2014
Vehicular accident in Lake Wales resulting in the release of sodium
hydroxide. There was a 1 mile radius evacuation ordered by Polk
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County Fire Rescue. There were no injuries. The solution was released
into a drainage area where the Kissimmee River could be affected.
Portions of SR 60 were closed during the cleanup effort.
December 12, 2014
Anhydrous Ammonia release at Haines City Citrus Growers packing
plant. The ammonia did not go off site and there were no injuries. The
area near the release was evacuated until it was contained.
December 18, 2014
Anhydrous Ammonia release at Commercial Warehouse in Winter
Haven while removing ice from a valve. The local area was evacuated
and there were no injuries. The ammonia did not go offsite.
January 22, 2015
Airplane crash into a building. Two persons on board the airplane were
killed. Sulfuric acid was in the warehouse and was consumed or diluted
in the resulting fire. No hazards went offsite and there was no
evacuation.
Potential Impacts
Significant potential impacts to people and property may be caused by a major chemical spill.
Probability of Future Occurrences
Polk County has programs that work to reduce the amount of hazardous materials and future
occurrences including:
1) In the Small Quantity Generator Program, the County provides businesses with information
about methods of hazardous waste recycling and disposal. Polk County is mandated by the State
to monitor all businesses on the handling of hazardous waste.
2) The Household Hazardous Waste Collection Facility accepts, free of charge, any household
materials (corrosives, flammable, reactive materials, and toxins) that can cause injury or are
harmful if handled improperly to people and the environment.
3) The County receives about 3,000 gallons of latex and oil-based paints and stains annually. A
portion of this material is in good, usable condition. In the Paint Giveaway Program, the good
paint is free to County residents and is available on a “first come, first served” basis.
4) The Polk County Household Used Sharps Collection Program is a health and public safety
program that disposes of over 1.5 million used needles and syringes (sharps) per year. Sharps
that are thrown away with household garbage place people in danger of injury by puncturing or
lacerating skin and spreading disease.
The probability of future occurrences is moderate.
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Phosphate Mining Industry
Description and Background
Approximately 420,000 acres or 30.6 percent of Polk County was categorized as mineable for phosphate
rock by the Florida Department of Environmental Protection (FDEP) Bureau of Mining and Minerals
Regulation (BMMR). Since the early 1900’s the phosphate mining industry has been second only to
agriculture in the economic impact of Polk County. The industry's impact on the Polk County economy is,
however, in decline and is anticipated to continue to decline in the 21st Century as phosphate mining
moves south into Hardee and DeSoto Counties. Some chemical manufacturing plants will continue to be
located in Polk County and may convert to process new phosphate products. In 2009, approximately
188,000 acres or 14 percent (14%) of the County remained designated with the Phosphate Mining
Future Land Use designation for active mining or industries to support the phosphate industry.
Phosphate mining is considered a temporary use of the land and the majority of the PM district has
been mined and is now very rural in nature due to reclamation after mining. (Polk County Bone Valley
Selected Area Study Existing Conditions Analysis)
The main waste products of phosphate mining are generated during the beneficiation and processing of
phosphate rock:
sand tailings and
phosphatic clays. Tailings are commonly
used to backfill mine cuts, then the
overburden stockpiled nearby is spread over
the tailings to produce a stable land form
with a variety of potential uses. The
phosphatic clays are pumped as a 3 to 5
percent solids slurry to large, diked areas
where the clay solids slowly settle and the
supernatant water is removed through
spillways and reused in the mine
operations.These clay settling ponds have
typically occupied 20 to 40 percent of the
land area mined. It takes 3 to 5 years to
consolidate to a 15 to 20 percent solids level
and to crust over enough to support cattle
grazing. (Central Florida Regional Planning Figure 4.30: View of a chemical plant. Source:
www.fluoridealert.org
Council 1997 Strategic Regional Policy Plan)
Chemical Fertilizer Plants
The phosphate rock is recovered by open pit mining. The phosphorus content of the phosphate rock is
in a form (calcium phosphate) that will not dissolve in water and cannot be absorbed by crops. As a
result a chemical process is needed. The chemical processing of phosphate rock (through the wetphosphoric acid process) to produce phosphoric acid is completed in large phosphoric acid-based plants
producing finished products such as di-ammonium phosphate, triple superphosphate and monoammonium phosphate. A primary and significant by-product of the wet process phosphoric acid based
products is phosphogypsum which is largely calcium sulfate.
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Gypsum Stacks
Phosphogypsum is stored in huge piles called
"gypsum stacks". In Central Florida, one of the
major phosphoric acid producing areas, the
industry generates about 32 million tons of
phosphogypsum each year. (US EPA)
The phosphogypsum, separated from the
phosphoric acid, is in the form of a solid/water
mixture (slurry) which is stored in the open-air
gypsum stacks. The gypsum stacks form as the
slurry containing the by-product phosphogypsum
is pumped onto a disposal site. Over time the
solids in the slurry build up and a stack forms. The
gypsum stacks are generally built on unused or
mined out land on the processing site.
Figure 4.31 View of a phosphogypsum stack. Source:
www.fluoridealert.org
As
the
gypsum
stack
increases,
the
phosphogypsum slurry begins to form a small pond (gypsum pond) on top of the stack. Workers dredge
gypsum from the pond to build up the dike around it and the pond gradually becomes a reservoir for
storing and supplying process water. The surface area covered by gypsum stacks ranges from about 5 to
740 acres. The height ranges from about 10 to 200 feet.
The tops of operating phosphogypsum stacks are covered by ponds and ditches containing process
water. Saturated land masses protrude into the ponds. These surface features may cover up to 75
percent of the top of the stack. Other surface features include areas of loose, dry materials; access
roads; and thinly crusted stack sides. (US EPA)
Historical Occurrences
The Dam/Levee Failure section outlines the historical occurrences of dam/levee failures including clay
settling ponds and gypsum stacks including the 1997 breach that occurred in the wall of a gypsum stack
in Mulberry maintained by the MPI
phosphoric acid/fertilizer production
facility. As a result of the breach,
approximately 50 million gallons of acidic
process water overflowed and ran into
and through Skinned Sapling Creek into
the Alafia River. Over the course of the
next week to ten days, the released
process water traversed approximately
35 miles of the Alafia River to Tampa
Bay. The release lowered the pH of the
Alafia River for several days, and added
large amounts of nutrients to the river
system, causing injuries to freshwater
wetlands and surface waters, resulting in
Figure 4.32: Sinkhole in Center of IMC-Agrico Waste Stack
death of many species of fish, crab and
Near Mulberry, June 1994 Source: www.fluoridealert.org (AP Photo)
shrimp, oysters and birds.
Several
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restoration projects in the Alafia River were undertaken (NOAA).
Another significant occurrence of note, in June 1994 a sinkhole formed (106 feet wide by 185 feet deep)
in the center of an IMC-Agrico gypsum stack (at the now Mosaic New Wales Plan) near Mulberry. The
sinkhole photo below which was taken July 13, 1994, released 20.8 million pounds of liquid phosphoric
acid into the ground below. The spill was able to be cleaned up before it harmed the drinking water
supply.
The County does not have any available records on historical occurrences of dam/levee failures.
Internet research resulted in the following historical occurrences:
Date: June 1994
Location: IMC-Agrico, Florida
Company: IMC-Agrico
Type of Incident: Sinkhole opens in phosphogypsum stack
Release: not determined
Impacts: Release of gypsum and water into groundwater
Source: www.wise-uranium.org
Date: October 1994
Location: Fort Meade, Fl
Company: Cargill
Type of Incident: Not indicated
Release: 76,000 m3 of water
Impacts: spill into Peace River near Fort Meade
Source: www.wise-uranium.org
Date: December 7, 1997
Location: Mulberry Phosphate, Polk County
Company: Mulberry Phosphates, Inc
Type of Incident: Phosphogypsum stack failure
Release: 200,000 m3 of phosphogypsum process water
Impacts: Biota in Alafia River eliminated
Source: www.wise-uranium.org
Date: October 2, 1994
Location: Payne Creek Mine, Polk County
Company: IMC-Agrico
Type of Incident: dam failure
Release: 6.8 million m3 of water from a clay settling pond
Impacts: Majority of spill contained on adjacent mining area: 500,000 m3 released into Hickey
Branch, a tributary of Payne Creek
Source: www.wise-uranium.org
Date: December 3, 1971
Location: Fort Meade, Fl
Company: Cities Service Co.
Type of Incident: Clay pond dam failure – cause unknown
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Release: 9 million m3 of clay water
Impacts: Tailings traveled 120 km downstream with Peace River, large fish kill
Source: www.wise-uranium.org
Date: March 1967
Location: Fort Meade, Fl
Company: Mobile Chemical
Type of Incident: dam failure – cause unknown
Release: 250,000 m3 of phosphatic clay slimes, 1 million m3 of water
Impacts: Spill reaches Peace River, fish kill reported
Source: www.wise-uranium.org
Potential Impacts
The extent of damages that the County would suffer will depend on the exact location of a dam breach
and the degree of the failure. Due to their isolated locations, there is little likelihood that the failure of a
clay-settling pond would adversely impact county residents. Concerns with clay-settling ponds and
phosphogypsum stacks are centered primarily on the potential for the contaminated water flowing into
water bodies and water supplies and its subsequent environmental impacts.
Possible effects of the failure of a gypsum stack include surface and groundwater contamination.
Radium is a trace impurity of gypsum. Many parts of the nation have naturally occurring radiation.
Some areas of Polk County have higher recordings of radiation.
Probability of Future Occurrences
Although phosphate mining is declining in Polk County, the wet-phosphoric acid process continues at
the chemical plants as mined phosphate from other
counties is transported to Polk County. A continued
probability exists for threats generated by both the
chemical plants and the gypsum stacks.
Pipelines
Description and Background
Four pipelines currently traverse Polk County and
include the Ammonia Pipeline, the Central Florida
Pipeline, the Florida Gas Transmission Company (FTC)
Pipeline, and the Gulfstream Pipeline. All of these
pipelines carry hazardous materials. A fifth pipeline is
proposed, the FSC Pipeline. The location of the
pipelines is provided in Figure 4.33.
Figure 4.33: Pipeline Locations
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Historical Occurrences
There are no recent recorded occurrences of pipeline incidents in Polk County.
Potential Impacts
Pipelines are generally viewed as a safe an efficient method to transport hazardous materials. Potential
impacts from an accident or incident are potentially disastrous.
Probability of Future Occurrences
There is a low probability of future occurrences. Public education regarding pipelines such as “Call
before you dig” is important to overall public safety. Many local governments in Polk County
disseminate information about pipelines.
Railroads
Description and Background
The movement of people and materials throughout the county has increased. Accompanying this
movement is the increased risk of disaster involving rail. According to information obtained from the
Florida Department of Transportation, there are 1,905 rail crossings in Polk County, 97 percent of which
are located in the unincorporated areas of Polk County. In the incorporated areas, the rail crossings
impact nine of the 17 jurisdictions. Of these, the City of Lakeland has the most rail crossings (23
crossings), followed by the City of Bartow (11 crossings), and the City of Lake Wales (6 crossings). Figure
4.35 illustrates the locations of the rail crossings.
Rail Crossings by Jurisdiction
25
20
15
10
5
0
Figure 4.34: Rail Crossings by Jurisdictions Source: FDOT
CSX moves freight through the county. The Amtrak Silver Star running from New York and Miami has
stops in Lakeland and Winter Haven. Lakeland’s Amtrak train station is located at the northeast corner
of downtown along Lake Mirror, east of Massachusetts Avenue. The Winter Haven Amtrak Station is
located on 7th Street SW across US 17.
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Figure 4.35: Rail Crossings by Jurisdictions Source: FDOT
Historical Occurrences
One of the most disastrous train accidents in Polk County occurred in March 7, 2012.
March 7, 2012
A CSX Railroad Train and a fuel tanker truck collided causing 3,000
gallons of diesel to be released and burned causing a wildfire. The
driver of truck was killed and SR 60 was closed for an extended period
of time. The accident occurred on Mosaic property west of Bartow.
Table 4-20 provides a 10 calendar year history of accidents and incidents for all railroads in Polk County
and Table 4-21 provides total accident/incident information. The data in the tables is from the Federal
Rail Administration.
IV-64
Polk County Multi-jurisdictional Local Mitigation Strategy
August 18, 2015
SECTION IV: HAZARD IDENTIFICATION AND ANALYSIS
TABLE 4-20:
10 YEAR ACCIDENT/INCIDENT OVERVIEW BY CALENDAR YEAR (CY) FOR ALL POLK COUNTY RAILROADS
Category
CY
‘06
Total Fatalities
CY
‘07
CY
‘08
CY
‘09
CY
‘10
2
6
2
6
13
14
1
10
Trespasser deaths, not at crossings
2
1
2
3
Trespasser injuries, not at crossings
1
1
1
Total Non-Fatal Conditions
Passengers injured in train accidents
Total
Source:
3
18
Federal Rail Administration
24
6
20
10
CY
‘11
CY
‘12
CY
‘13
CY
‘14
Total
1
1
3
1
22
8
9
8
10
83
1
1
11
1
1
1
1
6
1
1
1
6
14
128
12
10
12
12
TABLE 4-21:
TOTAL ACCIDENT/INCIDENT RECORDS
Railroad
Total Accident/Incident Records
CSX Transportation (CSX)
117
Amtrak (ATK)
65
Florida Midland Railroad Company, Inc (FMID)
3
Conrad Yelvingon Distributors, Inc. (CNYX)
1
Florida Central Railroad Co. (FCEN)
1
Total
Source:
187
Federal Rail Administration
Potential Impacts
The extent of damages that the county would
suffer from train accidents greatly depends on the
type of train (passenger or freight) and/or its load
(i.e. hazardous materials).
Probability of Future Occurrences
The probability of a potential railroad incident is
noted as moderate.
Figure 4.36: CSX Phosphate Train, Broadway & Polk St.
Crossing, Bartow, Florida Source: www.bestofpolk.com
IV-65
Polk County Multi-jurisdictional Local Mitigation Strategy
August 18, 2015