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Tornadoes
Scott Dills,
Jennee Marlowe,
Ashley Stewart,
and
Noah Woodiwiss
EES Research Project
Scott Dills
Jennee Marlowe
Ashley Stewart
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Noah Woodiwiss
Tornadoes
The National Weather Service defines a tornado as “a violently rotating column of
air in contact with the ground and pendant from a thunderstorm.” So a tornado begins
with a thunderstorm. All thunderstorms have rising air called updrafts that supply warm
humid air that gives thunderstorms their energy. Tornadoes are formed when this rising
air or updrafts begin to spin and tilt the air from horizontal to vertical. Funnel clouds are
produced first from this rotation as air rushes into the vortex and pressure lowers. When
a funnel cloud touches the ground, it becomes an official tornado. Tornadoes on the
average are 400 to 500 feet wide with winds that usually reach no more than 250mph.
They get their ominous look from all the dirt and debris collected from the ground. Some
tornadoes have been known to turn red because of some clay that has been sucked into
the vortex.
Tornadoes can be extremely dangerous because of their forceful winds, which can
hit and destroy objects hundreds of yards away from the tornado. To determine how
dangerous a tornado is the Fujita scale was created. The Fujita scale assigns a number to
a tornado that categorizes how strong and damaging its winds are. A F0 tornado has
winds from 40-72 mph and minimal damage occurs. A F1 tornado has winds from 73112 mph and causes minimal damage to roofs, mobile homes, and cars. A F2 tornado has
winds from 113-157 mph and causes considerable damage. A F3 tornado has winds from
158-206 mph and can uproot trees, tear roofs off of stable houses, and overturn trains. A
F4 tornado has winds from 207-260 mph and can throw cars and level houses. A F5
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tornado has winds from 261-318 mph and can damage steel and concrete structures as
well as lift/throw houses and cars in the air. A F6 tornado has winds from 319-379 mph
and is called an “inconceivable tornado” because it’s very unlikely that one like this
would ever occur. The damage would be off the scales.
To predict tornadoes, the National Weather Service has Doppler radars all across
the U.S. These radars are mounted on towers that are 90 feet high. There are about 150
of them across the country. These Doppler radars detect the change in air movement,
which can help with early detection of tornadoes or detection of the right conditions for a
tornado. According to John Hart, a senior forecaster at the Storm Prediction Center in
Oklahoma, “Despite decades of research, we are still not able to predict the actual path of
a tornado.” So even though there are radars to try to predict tornadoes and give early
warning about tornadoes, there is no way yet to be able to predict the way a tornado will
head on its rampage or where and when one will develop exactly. Besides Doppler
radars there are also five satellites, which orbit the earth, and help detect suspicious cloud
formations that could stem tornadoes. However, even if a tornado warning is issued, it
only gives those in its path about ten to twenty minutes to escape. It is hoped that
sometime in the future there will be a system for being able to know exactly where a
tornado will form and the path it will take. Until then, radar, satellites, and storm chasers
will allow us to learn more about tornadoes.
So when and where are tornadoes most likely to hit? Well, research shows that
most tornadoes occur in the central U.S., which is often referred to as “Tornado Alley.”
These tornadoes occur mainly during springtime. The region that makes up tornado alley
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goes from Iowa to Oklahoma to Mississippi and forms an L-shape. Out of these
Oklahoma has the biggest threat.
If a tornado does hit, there are certain things everyone should know to be safe.
People should seek shelter in a strong building and not in a car or out in the open. Many
people think that seeking shelter underneath overpasses is a good idea, but this is one of
the worst places to seek shelter. Have a storm kit ready in your house with flashlights,
first aid, and snacks to take with you into your shelter. Know the difference between
tornado watches and tornado warnings. Tornado watches mean the conditions are right
for a tornado, and tornado warnings mean a tornado has been spotted. If all of these
safety tips are adhered to, chances of surviving a tornado are greater.
It has been said many times in the past that water spouts are simply tornadoes that
are over water. However, it has been suggested that this information is inaccurate. Water
spouts have the appearance of a tornado, with similar funnel cloud formation and swirling
winds. They are formed during similar times, namely, during unstable weather
conditions or while a cold front and a warm front collide. Water spouts are different
from tornadoes in one major way: a water spout is formed over the ocean.
While over the ocean, a water spout poses as no immediate threat to mainland
property and residents. They are only thought to be dangerous to boats or yachts that are
out on the water during the water spout’s lifetime. However, if a water spout were to
reach land, which has happened in the past, the y are no longer considered a water spout.
The funnel has now moved into the category of “tornado.” The change in name is due
not to a change in the storm, but rather a change in the debris of the storm. A water spout
is made of wind that has picked up water, ocean or lake water for example, and that water
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is what gives the funnel its appearance. A tornado gets its appearance from the debris it
picks up from land and carries while it is on its rampage.
A tornado that has resulted from a water spout reaching the main land will
dissipate quickly, VERY different from a tornado’s ability to increase in strength if it has
formed over land. However, there will always be an exception or two to this statement.
You may recall the tornado that struck the city of Miami, Florida a few years ago. This
tornado started out as a water spout over the Atlantic Ocean. The water spout increased
in strength and headed for the coastal city of Miami. The citizens of Miami had little
time to act, and before there was much of a warning, the water spout had struck the main
land and a tornado was reported
A water spout has two kinds of movement to it. The first movement is the
cyclical movement of the vortex, the wind spinning around and around forming the
funnel of water that we see with the naked eye. The other movement is the lateral
movement that the funnel makes with the storm it is a part of. The funnel will not move
freely on its own. It needs to remain a part of the storm front that is passing through.
Wherever the storm that created the water spout moves, that’s where the spout itself will
move.
As stated, the formation of a water spout is very similar to the formation of a
tornado. Usually, two weather fronts will meet, warm and cold, and there will be a
reaction in nature. The fronts begin to pass each other very rapidly, and the winds of
these fronts will begin to flow by each other and will spin more and more rapidly. As
the winds begin to spin, they also begin to increase their altitude, and a massive updraft
will take place. As the updraft begins to take shape, the water vapor in the atmosphere
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begins to cool and steam is formed. That steam is what gives the water spout its initial
appearance. Soon after the funnel is formed, the winds of the vortex will begin to pick up
water from the ocean/lake the spout has formed over, which is where the spout gets its
name from.
Similar to a tornado, once the water spout has dissipated, all of the debris the
funnel has picked up will be dropped. All that will remain is the mild winds that were
once the funnel of a strong and possibly dangerous storm.
Water spouts can be seen on nearly any part of the U.S. coastline. One scientist
from the National Oceanic and Atmospheric Administration has claimed that the most
common place to observe a water spout is in the Florida Keys. He estimates that there
are between 400 and 500 water spouts in this area per year, and that number could
possibly be higher. For a water spout to form there are two major ingredients that are
necessary, both of which the Keys are known for. First is shallow water. The more
shallow the water, the greater the water temperature can be, and more water vapor will be
made. Second is wind. The Florida Keys are known for the “Trade Winds” which flow
across the Keys from an eastward to westward direction on a daily basis. These winds
allow the clouds to line up and meet each other, which is necessary for a storm of this
origin to form. In this area, water spouts are most likely to form from 4 to 7 p.m., with
11 a.m. to 1 p.m. being the second most popular time range for the formation. The Gulf
of Mexico has seen its share of water spouts, mainly on the Florida coast, with Tampa
Bay being the hotspot for these storms. The Atlantic Coast, from Miami up to
Chesapeake Bay in Virginia, is another area where water spouts are more likely to form.
The Pacific coast has seen its share of water spouts also, but storms on the west coast
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tend to be more weak than the storms of the east and live a much shorter life. Water
spouts have even been reported over the Great Lakes in the midwest and over the Great
Salt Lake of Utah.
Tornadoes affect the biology of the areas that they touch down in very much. The
tremendous winds coming from the tornado can knock down trees, move soil and water,
and destroy crops. Beyond destroying nature, they can also destroy houses and people’s
property. Whenever a tornado moves through an area, it may even destroy something
that can end up causing a fire changing the biology of the area even more. Plants and
wildlife in the areas are always greatly affected by tornadoes.
Whenever trees are knocked down, this appears that the area has been destroyed.
The trees obviously were uprooted, but they actually now provide a new type of habitat
for different wildlife to be able to live in the area. The destruction of trees is like a
natural clear-cut area, but is not as harmful to the environment because it occurred
naturally. Of course, the knocking over and removal of trees can cause them to fall on
buildings destroying people’s homes and places of business. They trees can also knock
down power lines which hinders people’s lives and could even possibly start fires. The
fires would then destroy the area that they come in contact with.
Some of the major problems from the storms tornadoes come from include flash
floods, damaging winds, hail, and lightning. The flash floods that can accompany severe
storms actually kill around 146 people annually. The flash floods also can change the
biology of the land because land can be destroyed, but these floods may also have a
geological affect on the area. The streams and flood plains can be greatly changed and
many sediments are moved during flash floods. The winds also cause much dama ge
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because they can reach up to 140 miles per hour. Hail comes in various sizes and may
even reach the size of a grapefruit. The hail causes much damage to property beyond the
winds from the tornado. Lightning is one of the final big factors that can be a result of
the storms. Beyond lightning killing between 75-100 people a year, it also can strike the
land and possibly cause fires which would change the local biology. All of these
problems can greatly affect the biology of land.
Dust devils and waterspouts are similar to tornadoes, but are not quite as
destructive. Dust devils are smaller whirlwinds that are not actually tornadoes and occur
in very dry areas. The only damage they do is move dry, loose objects from one place to
another. There is not much more destruction than moving dirt from one spot to the next.
Waterspouts are smaller types of tornadoes, but they occur in water. They can become
rather large, but generally are not very destructive until they actually move onto the land.
They mostly just move water out of lake or the ocean, and they may destroy houses or
boats in the area.
The geology of tornado areas is affected in somewhat the similar ways because
there are not many processes that occur beyond wind. The wind and waterspouts moves
sediments from one area to another. The flash floods are the main thing that causes
change in the local geology during tornadoes. Sediments are deposited and sand dunes
may even develop on a small extent but nothing large. Geologic forces do not cause
tornadoes to occur either, they occur by meteorological forces.
The area a tornado blows through can be stripped of all plant life. This would
bring a lot of harm to that area and may take a very long time for the area to be the way it
is supposed to be. Also, if the land is bare, then much erosion is probably going to occur
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during this point in time until plant life can come back to the soil. The strong winds that
occur for a short period of time can also cause physical weathering on the rocks that are
in the area. But this is not anything very noticeable because the winds do not last for a
very long time.
Geology affects where tornadoes occur more than tornadoes have an affect on the
geology. The majority of tornadoes that occur in the United States develop in the
Midwestern states. This is because the area is extremely flat and allows for the tornadoes
to continue in a straight pattern with constant wind speeds. Tornadoes can occur in hilly
areas, but rarely do they occur in very mountainous areas because the terrain is too rough
for the tornadoes to stay straight. The meteorology of the Midwest and other flat areas
around the world is also different from the mountainous areas, but this weather is perfect
for tornadoes.
Crops can also be destroyed in the path of a tornado. Most of the United States
wheat is grown in the Midwest where many tornadoes occur. Large tornadoes come
through and can completely destroy entire farms of wheat, corn, and livestock. The
stronger tornadoes can destroy large areas completely, but some of the smaller tornadoes
may only have a small affect on the areas.
Along with all these effects from tornadoes, they can also wreak havoc
economically. Ways tornadoes can cause economic damage include: crop loss, loss of
livestock, and damages to houses, farm machinery, trees, buildings, automobiles, trucks,
trains, airplanes, and utility services.
Economic damage with tornadoes increases with time. This is true for two main
reasons. First inflation is natural in our current free- market economic system, and second
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of all, because, except in times of recession, businesses and people acquire more wealth
over time. There have been some examples over time of the terrible power which
tornadoes possess. The Oklahoma City tornado in 1999, for instance caused $1 billion
worth of damage to infrastructure alone. Since 1890, there have been 138 tornadoes that
have committed more than $50 million in damage. Perhaps the most financially
devastating tornado in United States history was the 1896 Saint Louis tornado, which
ripped a path through eastern Saint Louis, destroying over $2.9 billion.
In 2001, there was a series of 400 tornadoes that affected 18 states and created
billions of dollars of damage and sent insurance companies reeling for weeks. Cold dry
air from the Rocky Mountains collided with warm, wet air from the Gulf. More than fifty
percent of the damage all occurred in three days, from May 4 to May 6. Insurance
companies took major heat from these tornadoes. Morgan Stanley lost over $200 million
in the Oklahoma City area alone. State Farm Group lost $50, Zurich Group - $48,
Allstate received 531 claims from the area. According to State Farm, the states that were
hit the hardest were Tennessee with 6,800 homeowners and 7,200 auto claims, Missouri
with more then 5,300 homeowners and 5,600 auto claims filed, Illinois with 4,300
homeowners and Texas with 7,200 auto claims. The fact that all this damage occurred in
a week displays some of the power that tornadoes contain.
These days, urban damage has become much more common in great part because
of the rises in urban sprawl. Despite this, tornadoes that cause massive damage only
occur approximately once per decade in the United States. This is by no means a pattern,
simply an average. A major challenge that arises is the capacity for preparedness and
recovery. This is made possible by maintaining readiness during the gaps between the
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tornadoes. Insurance and reinsurance industries have to spend these times to prepare for
the next occurrence.
A tornado by mere definition is a truly awe-inspiring phenomenon. From their
origins all the way to their often destructive ends, tornadoes defy logic with massive wind
speeds, fast travel paths, and huge capacities for damage. An understanding of the
natural world is invaluable to us who live as a part of Earth’s ecosystem. Studying
tornadoes can help us avoid the dangers they present, and gain a greater knowledge of the
world around us.
Scott Dills
Jennee Marlowe
Ashley Stewart
Noah Woodiwiss
Works Cited
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<http://www.nssl.noaa.gov/users/brooks/public_html/damage/tdam1.html>.
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<http://www.spc.noaa.gov/faq/tornado/index.html>.
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