Do Tornadoes Really Twist

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Tornadoes
Information gathered by Stacy Wiley and Sierra
Carter in preparation for the festival El Nino,
La Nina, and me!
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What is a
?
a violent destructive whirling wind accompanied
by a funnel-shaped cloud that progresses in a
narrow path over the land
(www.m-w.com)
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Tornado Causes
Thunderstorms Hurricanes El Niño/ La Niña ?
Unstable atmosphere!!
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Tornado Formation
First, you have two patches of air moving towards
each other warm, moist air from below and cooler
air from above
Next, the warm air rises and the cool air comes
down to take its place. This causes a horizontal
spinning patch of air to form close to the ground.
Finally, the spinning air is pulled vertically by
an updraft, a draft of air that is close to the
ground and then moves upwards.
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Close Up to the Twister
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Where do tornadoes occur worldwide?
The majority of tornadoes occur in agricultural
areas. Tornadoes need moisture to feed their
parent thunderstorms and the instability
associated with spring and summer warming. Crops
need moisture to grow and the temperature
variation associated with changing seasons. Both
conditions for tornadoes and agricultural growth
are found in the same areas, as is shown on this
map. (Courtesy of Dr. T. T. Fujita, University
of Chicago)
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Where do tornadoes occur in the US?
Why Tornado Alley? The land in the Great
Plains is relatively flat, which allows cold dry
polar air from Canada to meet warm moist tropical
air from the Gulf of Mexico. It's along the front
between the two air masses that most tornadoes
form.
Most tornadoes in the United States form in an
area called "Tornado Alley". This area includes
parts of Texas, Oklahoma, Kansas, and Nebraska.
These tornadoes are formed by thunderstorms.
Some of the tornadoes in the southern states such
as Florida, South Carolina, and Georgia are
caused by hurricanes.
http//www.windows.ucar.edu/tour/link/earth/Atmos
phere/tornado/alley.html
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Recent Killer Tornadoes

• 2005 is the first year recorded in history to
  have no killer tornadoes in April, May,
  June, or July
• August 18, 2005- Wisconsin, outbreak of 28
  tornadoes, 21 million damage, one death
• August 29, 2005- Georgia, F2, one of 32 caused by
  hurricane Katrina, destroyed a chicken house
  killing 375,000 chickens and one man
• September 24, 2005- Mississippi, one of 52 caused
  by hurricane Rita, killed one man while turning
  his mobile home over

These are the KILLER ones!
http//www.tornadoproject.com/recent/recentts.htm
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Note? means final number not yet available.
Important! Prelim. numbers represent tornado
reports. Columns marked Final represent total
tornadoes. 2005 numbers updated through 7 AM CDT
10/11/2005
http//www.spc.noaa.gov/climo/torn/monthlytornstat
s.html
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Effects of tornadoes

• Houses and other structures can be destroyed
• Wind damage
• People and animals can be killed
• Crops can be destroyed
• destruction of whatever is directly in the path
  of the tornado!!
• Large amounts of money required for rebuilding

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Weak Twisters
69 of all tornadoes Lifetime is 1-10 minutes or
more Winds less than 110 mph
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Strong Twisters
29 of all tornadoes May last 20 min. or
longer 110-205 mph winds
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Violent Twisters
Only 2 of all tornadoes Lifetime may exceed one
hour 205 mph winds or stronger
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The Fujita Scale

• The Fujita Scale is used to rate the intensity of
  a tornado by examining the damage caused by the
  tornado after it has passed over a man-made
  structure.
• To determine the Fujita scale rating, one may
  look for
• - The attachment of the walls and floor to the
  foundation of the building
• - The attachment of the roof to the rafters and
  walls
• Whether or not there are steel reinforcing rods
  in concrete or cinder
• block walls
• - Whether there is mortar between the cinder
  blocks

http//library.thinkquest.org/20698/data/fujita.ht
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F 0

• Gale Tornado
• Winds 40-72 mph
• Damages chimney, breaks tree branches, pushes
  over small trees, damages sign boards

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F 1

• Moderate Tornado
• Winds 73-112 mph
• Peels surface off roofs, pushes mobile homes off
  foundation or overturns, pushes moving cars off
  the road, destroys attached garages

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F 2

• Significant Tornado
• Winds 113-157 mph
• Considerable damage! Roofs torn off frame houses,
  mobile homes demolished, cars pushed over, trees
  snapped or uprooted, light object missiles
  generated

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F 3

• Severe Tornado
• Winds 158-206 mph
• Roof and some walls torn off of well constructed
  houses, trains overturned, most trees in path
  uprooted

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F 4

• Devastating Tornado
• Winds 207-260 mph
• Well constructed houses leveled, structures with
  weak foundation blown away some distance, cars
  thrown and large missiles generated

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F 5

• Incredible Tornado
• Winds 261-318 mph
• Strong frame houses lifted off foundations and
  carried considerable distances to disintegrate,
  automobile sized missiles fly through the air in
  excess of 100 meters, trees debarked, steel
  re-inforced concrete structures badly damaged

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El Niño and La Niña
Studies show that there are fewer tornadoes
during El Niño years. On the other hand, they
also show that tornadoes tend to be more
devastating during the La Niña period (F4,
F5). Outbreaks of violent tornadoes are more
likely after a La Niña year than an El Niño year
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Preparedness
A tornado watch is issued by the National Weather
Service when tornadoes are possible in your area.
A tornado warning is issued when a tornado
has been sighted or indicated by weather radar.
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What To Watch For

• When a watch or warning is posted and a possible
  tornado may occur, look for
• A dark, sometimes greenish sky
• A wall cloud
• Large hail
• A strange quiets that occurs during or after a
  thunderstorm
• Clouds that move by very fast, especially in a
  rotating pattern or converging toward one area of
  the sky
• A sound similar to a waterfall or rushing air
  initially that then turns into a roar as it moves
  closer it may sound like a train or jet.

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What to do
If you live in a mobile home, GET OUT! Mobile
homes are particularly vulnerable. A mobile home
can overturn very easily even if precautions have
been taken to tie down the unit. When a tornado
warning is issued, take shelter in a building
with a strong foundation. If shelter is not
available, lie in ditch or low-lying area a safe
distance away from the unit.
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At home
- Go at once to a windowless, interior room,
storm cellar, basement, or lowest level of the
building. - If there is no basement, go to an
inner hallway or a smaller inner room without
windows, such as a bathroom or closet. - Get
away from the windows. Opening windows allows
damaging winds to enter the structure. Leave the
windows alone. - Go to the center of the room.
Stay away from corners because they tend to
attract debris. - Get under a piece of sturdy
furniture such as a workbench or heavy table or
desk and hold on to it. - Use arms to protect
head and neck. - If in a mobile home, get out
and find shelter elsewhere.
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In a car

• - Never try to outdrive a tornado in a car or
  truck. Tornadoes can change direction quickly and
  can lift up a car or truck and toss it through
  the air.
• - Get out of the car immediately and take shelter
  in a nearby building.
• If there is no time to get indoors, get out of
  the car and lie in a ditch or low-lying area away
  from the vehicle.

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Do Tornadoes Really Twist?

• Storm chasers on the hunt for answers!

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Getting the kids involved
We will have a few of these bottled tornadoes
for the kids to shake up themselves to answer the
question, do tornadoes really twist? The
answer- of course they do!!
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Tornado Simulator
We will have this tornado simulator for the
students to observe a more realistic twister.
This one actually looks like swirling winds and
may give the kids a better idea of what tornadoes
look like.
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Storytelling
After our hands-on experiments and some short
discussion, we are going to have a storytime.
Our story will be related to Storm chasers on
the hunt for answers! We will incorporate more
information on tornadoes as well as involve the
kids using sound effects and motions for specific
words throughout the story.
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Tornadoes
Information gathered by Stacy Wiley and Sierra
Carter in preparation for the festival El Nino,
La Nina, and me!