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TORNADOE
S
What is a Tornado?A tornado is a violently rotating column of air that extends from a thunderstorm
to the ground.
(Watch Tornado Montage)
A tornado can have winds up to miles per hour.
About tornadoes occur each year in the United States.
are weak tornadoes that form over water.
Each year, approximately people lose their lives because of tornadoes.
Most tornadoes occur in , which stretches from Texas to Nebraska and also includes Colorado, Iowa, Indiana, Illinois, Kansas Missouri, and Arkansas.
What do you think???
300
1,000
Waterspouts
70
Tornado Alley
Basic Facts
• begin with a thunderstorm.
• can have damage paths that are greater than one mile wide and 50 miles long.
• usually move southwest to northeast, but are known to move in any direction.
• are most common in Tornado Alley, but they can happen ANYWHERE.
• are measured by The Fujita Scale.
Tornadoes…
• Tornadoes are most frequently reported east of the Rocky Mountains during spring and summer months.
• Peak Tornado season in the southern states is March through May; in the northern states, it is late spring to early summer.
• Most Tornadoes occur in Tornado Alley, which stretches from Texas to Nebraska.
• Occasionally, tornadoes develop so fast that there is very little warning.
• Although they usually occur between 3 p.m. and 9 p.m., they can happen anytime of the day.
Where and When are Tornadoes most likely to
occur?
What causes a Tornado?
• Tornadoes form when warm, humid air collides with cool, dry air.
• The cold air, which is more dense, is pushed over the warm air- this usually produces thunderstorms.
• The warm air rises through the colder air and this causes an updraft.
• If winds vary sharply in speed, the updraft will begin to rotate. This rotating updraft is called a mesocyclone (also known as a supercell thunderstorm).
• As the mesocyclone brings in more warm air from the moving thunderstorm, the rotation speed becomes faster.
• Cool air from the jet stream, a strong band of wind in the atmosphere, creates even more energy.
Click here and CAUSE YOUR OWN TORNADO.
• Water droplets from the mesocyclone’s moist air form a funnel cloud.
• The funnel cloud continues to grow and descends from the cloud.
• When the funnel reaches the ground, it becomes a Tornado.
How are Tornadoes Forecasted?
Doppler radar records wind speeds and identifies areas of rotation within thunderstorms.
This is how Tornado Watches and Tornado Warnings are issued.
Storm Chasers are researchers who follow storms during tornado season and place sensors in tornadoes’ paths. These sensors measure wind speed, barometric pressure, humidity and temperature.
Meteorologists at the U.S. National Weather Service use Doppler radar, weather balloons, satellites, and computer modeling to watch for severe storms or tornadoes.
Listen for a…
Tornado Watch- This means that tornadoes are possible. You should stay alert for approaching storms, watch the sky, and stay tuned to radio or television weather alerts.
Tornado Warning- A tornado has been sighted or indicated by weather radar. You should take shelter immediately.
Be Aware of Danger Signs
• Dark, often greenish sky
• Large Hail
• Large, dark, low- lying cloud (especially if it is rotating)• Loud roar, similar to a freight train
What should you do if you have been issued a Tornado Warning?
If a Tornado Warning is issued, take shelter
IMMEDIATELY!
If you are already in a house:• Get to a safe room (basement, cellar). You want to get to the lowest level of
the house.• If there is no basement, go to the center of an interior room on the lowest
level of the house.• Put as many walls between you and the outside as you can.• Get under a sturdy table and use your arms to protect your head and neck.• DO NOT open windows.
• Get out immediately and go to the lowest level of the nearest building or shelter home.
• Lie flat in a nearby ditch or depression with your hands over your head. Watch out for flooding.
• DO NOT get under an overpass or bridge. Most times, debris is collected in this area and you are always safest in a low, flat location.
• Watch out for flying debris. Flying debris is the cause of most deaths and injuries.
If you are in a vehicle or mobile home:
If you are outside with no shelter:
Tornado Damage
The Fujita Scale classifies tornadoes into differing intensities based on their estimated wind speed. This is done by assessing the damage of the Tornado
EF-0. Light damageWind 65 to 85 mph. Causes some damage to siding and shinglesEF-1. Moderate damageWind 86 to 110 mph. Considerable roof damage. Winds can uproot trees and overturn single-wide mobile homes. Flagpoles bend.EF-2. Considerable damageWind 111 to 135 mph. Most single-wide mobile homes destroyed. Permanent homes can shift off foundation. Flagpoles collapse. Softwood trees debarked.EF-3. Severe damageWind 136 to 165 mph. Hardwood trees debarked. All but small portions of houses destroyed.EF-4. Devastating damageWind 166 to 200 mph. Complete destruction of well-built residences, large sections of school buildings.EF-5. Incredible damageWind above 200 mph. Significant structural deformation of mid- and high-rise buildings.
The Enhanced
Fujita Scale
Group Science ActivityBuilding Your own Tornadoes
Click here for directions
• The science activity for today will be to create your own water vortex in your regular science groups.
• A vortex works with water a lot like a tornado works with air.
Test your Knowledgewith
Tornado Jeopardy
Basic Facts FormationWarnings/
Safety
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For more information on tornadoes, visit the links below
The Online Tornado Museum- Here, you can learn about previous tornadoes and the damage they caused.
Building a Safe House- Visit this site if you would like to see how you can build your very own safe room.
Brain Pop- Learn information and watch a movie about tornadoes and other storms.
Web Weather- A fun site where you can learn about weather and play games too!
