Storms, Flooding, Landslides Forget not the lessons learned from

Storms, Flooding, Landslides
• Increasing Impact of Severe Weather, Flooding, and Related hazards
Forget not the lessons learned from past disasters
because many have sacrificed their lives while we
learnt the lessons.
• Hurricanes/Typhoons & related storms
– and resulting flooding, wind damage, and coastal erosion
• Severe thunderstorms, Tornadoes
• Winter storms
- @Amodmanidixit
• Heavy rain and flooding
• Drought
• Wildfires – forests, grasslands, etc.
• Wind
• Flooding – where, how often, human interventions
• Landslides – causes and solutions
Storm/Landslide/Flooding news and information (updated often by Dr. Kuehn):
2015-16 Headlines
Storms and Flooding
Learning from the past, reducing risks for the future
* Billion-Dollar Weather and Climate Disasters: Overview
Policy: Hurricane Katrina’s lessons for the world : Nature News & Comment
Hurricane Matthew causes record flooding, matching FEMA flood maps
Build cities that work with nature not against it
Hurricane Matthew in pictures
Horrific rains and ocean surge: Hurricane Matthew by the numbers
2015-16 Headlines
We must build resilience into our communities
Post-Sandy Rebuilding for Resiliency: Lessons From Long Beach, NY | Steven Cohen
15 of the deadliest, most destructive hurricanes in US history
New Landslide Legislation to Help Alleviate Hazard Risks
Floods that hit New York City every 500 years now hit every 24 | New Scientist
$200M relocation project that moved a mountain to save Grundy, VA pays off
What Does A '100 Or 1000-Year Rain Event' Actually Mean? – Forbes
Sandy's Lessons Lost: Jersey Shore Rebuilds in Sea's Inevitable Path
Map of 56 years of tornado tracks
Hurricane Sandy, 2012: 285 deaths $71.4 billion damages
Hurricane Matthew
Hurricane Matthew
Storm Surge
• Death toll in
the hundreds
• More than a
Hurricane Matthew
Hurricane Matthew
Hurricane Matthew
Sandy's Lessons Lost: Jersey Shore Rebuilds in Sea's Inevitable Path
Forget not the lessons learned from past disasters
because many have sacrificed their lives while we
learnt the lessons.
Storm Surge
- @Amodmanidixit
Cost of Weather Disasters (Storms, Flooding, Landslides, Etc.)
•NOAA Billion Dollar Weather-Climate Disasters
West Virginia Economic Impact 1960-2005
Occurrence of Loss Causing
Hazard Events
Total Losses from Hazard Events
($2005 Millions)
water shortages,
losses, power
impacts, etc.
Major contributors to hurricane disasters:
can be up to 200 mph or more!
sometimes feet of rain in a day
Storm surge seawater floods the coast, sometimes resembles tsunami
Coastal erosion
Vulnerable cities and towns, especially in low coastal areas
2015 Sets a New Record for Category 4 and 5 Hurricanes and Typhoons
California through Washington had drought again in 2015, plus lots of fires. Texas got flooded instead.
2012 Hurricane Sandy
• Broke the record for largest storm in recorded Atlantic basin history
• Multi-billion dollar disaster impacting the most heavily-populated
part of the U.S.
• Widespread flooding due to heavy rain and storm surge
• Sea level rise made it worse, perhaps adding a billion $ to the cost
•Before & After Photos
Flooding is a natural river (and coastal) process. Most floods result
from heavy rainfall, rapid snow melt, or a combination of both.
During a river flood the amount of water (discharge) is more than will
fit in the river channel, and the excess spills out onto the flood plain.
•Pictures: Floods, Fire, Snow in the Aftermath
Flooding becomes a problem when people get in the way.
•Hurricane Sandy: Death Toll Rises, Costs Could Reach $50 Billion
•NASA Warned New York About Hurricane Danger Six Years Ago - Scientists told
us a storm like Sandy would be catastrophic
•USGS Responds to Hurricane Sandy
•USGS Flood Information on Sandy
1996 flood in Liuzhou, China
Flooding is a normal river and stream
process. This city is built on a river floodplain as are many other cities.
NOAA flood monitor:
Flood frequency
The recurrence
interval for the largest
flood often is
estimated based on
data for smaller
floods. Forecasting
based on past flood
history only works if
enough data has been
collected and the river
system hasn t been
changed significantly.
Many river systems
have been changed by
human activity, and
this can have a big
effect on the accuracy
of flood probabilities.
Chapter 13 Understanding Earth
Current River Observations (US national map) or
The "100-Year Flood"
Fig. 14-29 Geology 2nd edition Chernicoff
Effects of Landscape Changes
Land clearing, fires, urbanization, destruction of wetlands, etc.
Flood-frequency curve for the
Skykomish River at Gold Bar, WA
Fig. 14-28 Geology 2nd edition - Chernicoff
A different river would have a different curve
Relationship between flood
size (discharge) and frequency
or probability of occurrence. A
ten-year flood has a 10%
chance of happening in any
particular year.
Fig 13.15 Understanding Earth
See also:
USGS Fact Sheet The 100-year Flood
USGS Fact Sheet Effects of Urban Development on Floods
Station information:
Older, 1982 map compared
to a newer, 1998 map.
The newer map uses both
more accurate land elevation
data and a more accurate
(larger) estimate of flood
USGS Open File Report 98-200
Improving Flood
Hazard Mapping
USGS Open File Report 98-200
Map of flood depth using the improved data.
USGS Open File Report 98-200
New laser mapping now helping to improve flood maps:
What can people do about flooding?
Mass Movement & Landslides
Research studies to better understand the problems
Make maps showing what areas are most hazardous
Educate people
Land use planning and zoning regulations for future development
(e.g. avoid building in the most hazardous areas)
• Disaster preparation
Hazard Maps
• Supplies
• Emergency plans & practice
Flooding Maps and Information,
• Control flood waters
Flood Insurance Rates, Guides
• Fix and improve levees
for Homeowners, Etc.
• Dams and retention ponds
• Build or improve flood channels and bypasses
• Raising existing houses (on fill or on stilts)
2015-16 Headlines
Mass movement includes all processes that transport large quantities of
rock, sediment, soil, etc. down a slope due to gravity. It occurs on
most slopes and can range from very slow to very fast. Heavy rain is a
common trigger.
Types of Landslides & Mass Movements:
Creep – really slow
Rock fall
Debris flows, earth flows, & mudflows
AGU Landslides blog
How Rain Turns Dirt into Disaster – Wired
* Videos and images of the 2015 mudflows in the Tehachapi Mountains, California - The Landslide Blog
* Dozens feared dead as hillside collapses on town in Guatemala
Human losses from landslides in Latin America and the Caribbean - The Landslide Blog
11,631 died over ten years; worst in places that combine people, steep slopes, and rain
* Bonne Nuit, Jersey: a strange place to build a new Care Home?
1995 landslide in La Conchita,
California Photos from U.S. Geological Survey
Learning from the past, reducing risks for the future
New Landslide Legislation to Help Alleviate Hazard Risks
Next: landslide video
Sample case study:
Landslides in São Paulo, Brazil: An integrated historical perspective
Ophir Chasma
landslide, Mars
The growing severity of floods and landslides in the state of São
Paulo, Brazil, is related to rapid environmental changes, such as
urbanization, deforestation and settlement in hazardous areas, rather
than to natural events, and unless more sustainable land-use practices
are adopted the impact of these (un)natural disasters might become
more severe.
For example:
Deaths from mudslides in Brazil
Creep is the slowest type of mass
movement. Almost all slopes consisting
of unconsolidated material creep a few
millimeters up to several centimeters
per year. Creep may produce tilting of
objects such as fence posts, telephone
poles, and retaining walls. It also causes
curved trunks in trees on creeping
slopes. Fig 11.11 Understanding Earth and NOAA
Types of rapid
mass movement
Geology - Chernicoff
Fig 11.16 Understanding Earth
Upper part of a slump
Geology - Chernicoff
Fig 11.8 Understanding
Rockfall is the fastest type of mass
movement. It occurs when loose
material falls from very steep or
vertical slopes.
Small rockfall in a road cut in the Blue
Mountains of Oregon S. Kuehn
More examples:
Fig 11.13 Understanding Earth
Debris flows, earth
flows, and mud flows
- composed of soil,
rock, other debris, and
Slump - a type of slide that
separates along a concave
surface. Slumps generally do
not travel far, and the
material within the slump
tends to move as a unit and
not become mixed.
Slump along a road
Debris flow deposits are often poorly
sorted and may contain boulders that
are larger than normal stream flow can
transport. Ancient debris flows can be
identified from similar deposits.
Fig 11.14 Understanding Earth
April 2015 debris flow in Floyd
County, KY damaged a house and
left deposits downhill of this photo
Landslide causes
Contributing factors:
balance of slope strength vs. gravity
• Type of slope material: sand, gravel, clay, bedrock, etc.
• How steep the slope is
• Amount of water (rain and storms)
• Vegetation (fire)
• Presence and orientation of fractures
or other zones of weakness
Illustration: the maximum stable slope
angle (angle of repose) for particles of
different sizes and shapes.
Possible landslide triggers:
• Rain
• Earthquakes
(some have no obvious trigger)
Frequency of landslides and
amount of precipitation in the
Seattle area.
Increasing the risk:
• Cutting into slopes to make them steeper
Water contributes to landsides by
adding weight and by lubricating
loose sediments.
• Building on or near unstable slopes
• Failing to control water runoff
Fig 11.6 Understanding Earth
Fire can remove vegetation and decrease slope stability thereby
increasing the potential for erosion and landslides
(especially debris flows)
Fractures along sedimentary40
bedding, Arizona
Enhanced erosion
following a fire near
San Luis Res., CA
Photo by S. Kuehn
Photo by S. Kuehn, October 2005
Cutting into slopes to build roads and
buildings increases the risk of mass
movement by making slopes steeper.
Fig 11.5 Understanding Earth
Photo by S. Kuehn
Fractured volcanic rocks and
fallen boulders at Pinnacles
National Monument, CA
Zones of weakness
such as fractures
and layers also
contribute to the
risk of mass
Reducing Landslide Risks
Identify hazardous areas
• Identify factors that increase the hazard
Small landslide
(slump and
earthflow) in a
road cut along
Hwy 70 in CA
• Computer models to understand hillsides
• Find and map past landslides
• Map areas with high landslide potential
Strengthen problem slopes
Control water
Leave highest-risk areas
Small rockfall in a road cut in
the Blue Mountains of Oregon
1994 landslide near
McClures Pass, Colorado
Avoid building on or near creeping slopes
Land use planning (avoid making it worse)
Watch out for early signs of movement and for evidence of past
mass movement. USGS OFR 95-213
Avoid steep bluffs with
unconsolidated sediments
January, 1997
USGS OFR 98-239
Make maps to show where the hazard is greatest.
March 24, 2014 Washington State Landslide
•At least 41 people killed
•Previous slides at same location in 1949, 1951, 2006; Lots of old slides in valley.
•1999 report warned of continued risk to town.
•Slide occurred during wettest March on record
* Before and After: Photos Show Mudslide's Destruction - NBC
* USGS Computer simulation of landslide
* USGS Landslide Report (preliminary) (see last page)
36 Oso landslide victims identified
The Steelhead landslide in Oso, Washington State
What Started the Mudslide? Satellite Image May Offer New Clues - NBC
With dozens still missing, Washington mudslide search lumbers on - CBS News
It s gone ; Washington community struggles after deadly mudslide - CBS News
see also:
Washington mudslide: Scientist warned of "potential for large catastrophic failure," - CBS News
Landslide in Oso, Washington
Control water and
improve drainage
Stabilize landslide-prone slopes
e.g. by build sufficiently strong retaining structures
Installing drain systems to
reduce the amount of water in
a slope can reduce the risk of
S. Kuehn, 2005
Shannon & Wilson, Inc.
Keller – Environmental Geology
Explore Online - Flooding
Water Science for Schools – elevated house, effect of pavement on flooding
Flood insurance subsidy revamp targets West Virginia hard
Flood Hazards, A National Threat
Mercer County continues flood mitigation efforts
Significant Floods in the United States During the 20th Century
Current River Observations (map)
Flood Warnings
Hourly Precipitation records
Flood mitigation: Mercer project must continue
Map and Hydrographs for our region,1,1,1,1,1,1,1&toggles=10,7,8,2,9,15,6
NWS Blacksburg VA and region
USGS Science – Natural Hazards
Flood, Stream Flow, and Drought Maps,map&r=us&w=real,map
Explore Online - Flooding
Landslides – more examples
Ohio – March 20, 2012
USGS list of major landslides by year
U.S. Geological Survey (USGS) Waterwatch
real time stream flow, daily/yearly/weekly stream flow, drought, flooding
AGU Landslides blog
National Weather Service - flooding, high/low flow
Hwy 410 in Washington State buried by major slide- Oct. 11, 2009 (See gallery
photos 1 & 11) (note warning
signs in advance of slide) (ultimate cause
uncertain; slide mechanism discussed)
(lots of good stuff on the blog about WA state landslides)
USGS Surface Water News
Principles of Flood Management
Flood Statistics – damages and loss of life
Rethinking Development on Floodplains article
(more stories about this slide) (more about this slide – stories,
photos, videos)
More about landslides
130-year history of landslides for La Conchita, California
USGS Landslide Hazards Program
Landslide info from VA Dept. of Mines, Minerals, and Energy
VA Natural hazards (business-oriented site)
About landslides and reducing the risks – WA State Dept. of Ecology
Landslide info from Calif. Emergency Management Agency
Kelso, WA landslide: amazing photos, landslide video, etc. (Aldercrest is best)
Southern California—Debris Flows in Wildfire Areas
Landslide hazard photos - NOAA Natural Hazard Slide set
Debris-Flow Hazards in the United States - U.S. Geological Survey
General overview of landslides
contains a computer-simulated landslide
Sliding Thought Blog – landslides in WA state