FEMA For Kids: Celebrating World Disaster Reduction Day

Celebrating World Disaster Reduction Day
Young Americans Prepare: Becoming Disaster Ready

Tornadoes

Introduction: Tornadoes are nature's most violent storms. Tornadoes must always be taken seriously. Tornadoes can be very dangerous -- sometimes even deadly. They come from powerful thunderstorms and appear as rotating, funnel-shaped clouds. Tornado winds can reach 300 miles per hour. They cause damage when they touch down on the ground. They can damage an area one mile wide and 50 miles long. Every state is at some risk, but states in "Tornado Alley" have the highest risk. Tornadoes can form any time of the year, but the season runs from March to August. The ability to predict tornadoes is limited. Usually a community will have at least a few minutes warning. The most important thing to do is TAKE SHELTER when a tornado is nearby.

Tornadoes are fascinating to children. Studying them incorporates earth science, history, writing, art, math, geography and other school subjects. Below are some lecture materials, suggested classroom exercises, and sources of more information that you can include in your lesson plans. We hope you will use this information especially during the week that encompasses October 14, 1998, which is celebrated as World Disaster Reduction Day in this country and around the globe.

Lecture #1: What is a tornado? (earth science, geography, reading)

Tornadoes come from the energy released in a thunderstorm. As powerful as they are, tornadoes account for only a tiny fraction of the energy in a thunderstorm. What makes them dangerous is that their energy is concentrated in a small area, perhaps only a hundred yards across. Not all tornadoes are the same, of course, and science does not yet completely understand how part of a thunderstorm's energy sometimes gets focused into something as small as a tornado.

Where do they occur? Whenever and wherever conditions are right, tornadoes are possible, but they are most common in the central plains of North America, east of the Rocky Mountains and west of the Appalachian Mountains. They occur mostly during the spring and summer; the tornado season comes early in the south and later in the north because spring comes later in the year as one moves northward. They usually occur during the late afternoon and early evening. During the spring in the Central Plains, thunderstorms frequently develop along a "dryline," which separates very warm, moist air to the east from hot, dry air to the west. Tornado-producing thunderstorms may form as the dryline moves east during the afternoon hours. Along the front range of the Rocky Mountains, in the Texas panhandle, and in the southern High Plains, thunderstorms frequently form as air near the ground flows "upslope" toward higher terrain. If other favorable conditions exist, these thunderstorms can produce tornadoes. However, tornadoes have been known to occur in every state in the United States, on any day of the year, and at any hour. They also occur in many other parts of the world, including Australia, Europe, Africa, Asia, and South America. (This information can be easily incorporated into a geography lesson.)

What type of damage can they do? The damage from tornadoes comes from the strong winds they contain. It is generally believed that wind speeds in a tornado can be as high as 300 mph. Wind speeds that high can cause automobiles to become airborne, rip ordinary homes to shreds, and turn broken glass and other debris into lethal missiles. The biggest threat to living creatures (including humans) from tornadoes is from flying debris and from being tossed about in the wind. It used to be believed that the low pressure in a tornado contributed to the damage by making buildings "explode" but this is no longer believed to be true.

How are they detected? Today, the development of Doppler radar has made it possible, under certain circumstances, to detect a tornado's winds with a radar. However, human beings remain an important part of the system to detect tornadoes, because not all tornadoes occur in situations where the radar can "see" them. Ordinary citizen volunteers make up what is called the SKYWARN (www.skywarn.org) network of storm spotters, who work with their local communities to watch out for approaching tornadoes, so that those communities can take appropriate action in the event of a tornado. Spotter information is relayed to the National Weather Service, which operates the Doppler radar and which issues warnings (usually relayed to the public by radio and TV) for communities ahead of the storms, using all the information they can obtain from weather maps, modern weather radar, storm spotters, monitoring power line breaks, and so on.

Can they be predicted? Yes, but only to a limited extent. Although the process by which tornadoes form is not completely understood, scientific research has revealed that tornadoes usually form under certain types of atmospheric conditions. Those conditions can be predicted, but not perfectly. When forecasters see those conditions, they can predict that tornadoes are likely to occur. However, it is not yet possible to predict in advance exactly when and where they will develop, how strong they will be, or precisely what path they will follow. There are some "surprises" every year, when tornadoes form in situations that do not look like the right conditions in advance, but these are becoming less frequent. Once a tornado is formed and has been detected, warnings can be issued based on the path of the storm producing the tornado, but even these cannot be perfectly precise about who will or will not be struck.

How long is a tornado usually on the ground? Detailed statistics about the time a tornado is on the ground are not available. This time can range from an instant to several hours. A typical time frame is about 5 minutes or so.

How fast do tornadoes move? As with tornado duration, detailed statistics about forward speed are not available. Movement can range from virtually stationary to more than 60 miles per hour. About 10 to 20 miles per hour is typical.

How do I know if it is a tornado or just a funnel? The definition of a tornado means that the vortex of rapidly rotating air must be in contact with the ground. This means that to be a tornado, the swirling winds must be at the surface, capable of doing damage. If you see debris (dust and other objects swirling in the winds), it is definitely a tornado, even if there is no visible funnel cloud. If you can't see debris with a funnel cloud, then it might be a tornado but you can not be certain that it is (or is not). A tornado can move over a surface with few objects to be picked up and swirled about, or you may not be able to see all the way to the surface beneath a funnel cloud because of intervening hills, trees, or buildings. All funnel clouds should be treated as if they are tornadoes, unless you can be certain that they will not touch down...and being certain about such things is difficult. Even if the funnel is not in contact with the surface when you first see it, that situation can change quite rapidly!

Lecture #2: What to do if a tornado occurs? (Subjects: reading, science)

Tornado warning signs:

An approaching cloud of debris can mark the location of a tornado even if a funnel is not visible.
Before a tornado hits, the wind may die down and the air may become very still.
Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.

Important tornado terms to know:

Tornado Watch -- Tornadoes are possible. Stay tuned to the radio or television news.

Tornado Warning -- A tornado has been sighted. Take shelter immediately! While earthquakes are thought to occur largely in the Western U.S., in fact many states are vulnerable for quakes, including Kentucky, Missouri, Tennessee, Texas, even New England.

Children should know to:

Listen to a radio or watch television for weather updates. If a tornado is coming you MUST seek shelter. An underground shelter is best, such as a basement or storm shelter. If you don't have a basement, find an inside room or hallway or closet on the first floor AWAY FROM WINDOWS.

If you are at school during a tornado, listen and do what your teacher says.

If you are outside and cannot get inside, lie flat in a ditch or ravine. Lie face down and cover your head with your hands.

If you are in a car, take shelter in a nearby building.

After a tornado, watch for broken glass and power lines that are downed. If you see people who are injured, don't move them unless they are in immediate danger. Call for help right away!

Tornadoes can be very scary. If you are scared, be sure to talk to someone about it.

Lecture #3: Tornado rating system (Science, physics)

Fujita - Pearson Tornado Scale

F-0: 40-72 mph, chimney damage, tree branches broken
F-1: 73-112 mph, mobile homes pushed off foundation or overturned
F-2: 113-157 mph, considerable damage, mobile homes demolished, trees uprooted
F-3: 158-205 mph, roofs and walls torn down, trains overturned, cars thrown
F-4: 207-260 mph, well-constructed walls leveled
F-5: 261-318 mph, homes lifted off foundation and carried considerable distances, autos thrown as far as 100 meters

Lecture #4: Tornado fact or fiction (Reading)

Fiction: Areas near rivers, lakes, and mountains are safe from tornadoes.
FACT: No place is safe from tornadoes. In the late 1980's, a tornado swept through Yellowstone National Park leaving a path of destruction up and down a 10,000 ft. mountain.

Fiction: The low pressure with a tornado causes buildings to "explode" as the tornado passes overhead.
FACT: Violent winds and debris slamming into buildings cause most structural damage.

Fiction: Windows should be opened before a tornado approaches to equalize pressure and minimize damage.
FACT: Opening windows allows damaging winds to enter the structure. Leave the windows alone; instead, immediately go to a safe place.

Lecture #5: Tornado Math

The tornado is moving at 20 miles per hour. It is headed toward Femaville, which is 10 miles away. How long will it take for the tornado to hit Femaville? The city hall building of Femaville has a large basement. There is a tornado approaching and many people have sought shelter in the basement. The people in the basement are: 15 staff members from city hall, the mayor and his secretary, 2 from the flower shop across the street, 4 from the diner next door, 4 members of the Smitty family, 3 members of the Gordon family and one policeman. How many people are in the basement?

The policeman leaves to help others outside and two people walking by, a delivery man and three members of the Lee family have now come to the basement. Now how many are there?

The tornado hit Femaville and no one was injured, but it caused some damage to buildings. This was the damage: $2,346 to the Gordon family house; $11,490 to the diner; $3,421 to the flower shop and $874 to City Hall. How much total damage was there in Femaville?

There was also damage to the mayor's car, of $973. Now how much damage was there?

Tornadoes have hit the state around Femaville almost every year for the past 10 years. Here are the number of tornadoes each year: 1989: 2; 1990: 1; 1991: 3; 1992: 4; 1993: 1, 1994: 1, 1995: 3, 1996: 3; 1997: 0; 1998: 2. What is the average number of tornadoes to hit near Femaville each year?

Activity #1. Draw posters illustrating what to do during a tornado. (Art)

Note: This artwork may be eligible to be posted on the FEMA for Kid's Web site. Visit the site at www.fema.gov/kids and look under the Disaster Connection: Kids to Kids icon.

Activity #2. What states are at highest risk for tornadoes? (Geography, art.)

Color a U.S. map with different colors marking the different risk for tornadoes.

Activity #3. Writing Assignments (Creative writing.)

Imagine that a tornado has struck your community. You and your family must evacuate your home and come to your school for safety until the disaster is over and it is announced that is it safe for everyone to return home.

Plan and write an escape route for your family to take from your house to school. Give clear travel directions.
Plan and write down a list of materials for the disaster supply kit you will bring with you to the school. All the supplies for the kit must fit in an average sized gym bag.
Imagine that you and your entire family must stay at school for three days. There is no electricity or telephone service. There are 300 to 400 other people staying in the school. What do you do to pass the time safely? What do you do about meals and sleeping?

Tornado Publications

Tornadoes . . . Nature's Most Violent Storms
National Weather Service #92052
(order through www.nws.noaa.gov/om/newspub.htm)

After the Tornado Coloring Book
American Red Cross ARC 2205
Order through your local chapter

Tornado Safety Tips
FEMA L-148

Hurricane, Tornado, Flood Preparedness and Family Disaster Plans video
FEMA 0-0115
Order by calling 1-800-480-2520

Internet Resources: