A tornado can be one of the scariest things in the world. People who have seen a tornado up close never forget it. A tornado is so frightening because it is so powerful. It can pick up an 18-wheel truck like a toy. It can rip trees out of the ground and send them fl ying through the air. It can peel pavement off a highway. A tornado can tear through a street of homes and leave them fl at. Tornadoes kill about 90 people in the United States every year. They cause billions of dollars of property damage.
In the United States most tornadoes happen in an area called Tornado Alley. Tornado Alley is in the center of the country. It runs north from Texas and goes mostly across Oklahoma, Kansas, Nebraska, and Iowa. Tornadoes are also common, though, in many other states in the Midwest and the South. Tornadoes can happen at any time of year, but most happen in April, May, and June. Most tornadoes occur between 3 P.M. and 9 P.M., which is usually the hottest time of the day.
What Is a Tornado?
A tornado is a very powerful windstorm. It is sometimes called a twister. This is a good description because a
tornado is a column of air that is turning, or twisting, very fast. A tornado is usually shaped like a cone or a funnel. It is wide at the top and narrow at the bottom. It is also very tall. The top of a tornado can be more than 10 miles (16 kilometers) high in the sky. The bottom of a tornado, where it touches the ground, is where the damage happens. The
wind speed in a tornado may be more than 200 miles per hour (320 kilometers per hour). Because the wind is so strong, tornadoes can cause terrible damage.
Most people want to get as far away from a tornado as they can, as fast as they can. Some people, however, want to get closer to tornadoes. They wait until the afternoon sky gets as dark as night. The clouds turn an ugly green color. The rain comes down hard. The sound of the rain is so loud that one person can’t hear another standing right nearby. That’s when the people called storm chasers jump into their cars and head toward the storms.
Who the Storm Chasers Are
Who are the storm chasers? Some people chase tornadoes because it’s their job. Most people who
Ted Fujita and the F Scale
Some tornadoes are more powerful than others. Scientists use something called the Enhanced F Scale to describe how powerful a tornado is. They give each tornado a number from EF0 to EF5. An EF0 tornado causes the least damage. An EF1 tornado causes more damage than an EF0. An EF2 tornado causes more damage than an EF1, and so on. EF5 tornadoes are the most destructive. They lift houses off their foundations and tear them to pieces. They rip the bark off trees. They carry cars the length of a football fi eld. In an EF5 tornado, the gusts of wind are stronger than 200 miles per hour (320 kilometers per hour).
The Enhanced F Scale used today is based on an original F Scale that was invented by Tetsuya “Ted” Fujita of the University of Chicago in 1971. He was an immigrant from Japan. He had a special talent for understanding storms. By the time he died in 1998, he had become known as Mr. Tornado.
chase tornadoes as a job are scientists. Most of these scientists are meteorologists. A meteorologist is a person who studies weather. Meteorologists go to school for years in order to become weather experts.
Meteorologists who study tornadoes want to learn more about them so they can better predict when and
where these powerful storms will strike. If people have more warning that a tornado is likely to strike, they
have more time to take shelter. That means they are more likely to survive a tornado unhurt.
To help make others safer, meteorologists who are storm chasers sometimes put themselves at risk. In cars or trucks full of special equipment to gather weather information, they drive to the area where the weather is worst.
Some other people who chase tornadoes as a job are photographers or fi lmmakers. They are able to sell dramatic pictures of tornadoes. Another kind of job for some storm chasers is taking people on storm-chasing tours.
A lot of people chase tornadoes as a hobby. For these people, storm chasing is fun and exciting. Sometimes,
things these people see or information they gather helps scientists who study tornadoes.
There are many kinds of storm chasers. They all have their part to play.
Tornadoes are usually caused by powerful thunderstorms, along with thunder, lightning, hard rain, and hail. The storm clouds that produce tornadoes are called supercells. In a supercell, warm air is pulled in at the bottom of the cloud. The warm air then rises up into the sky.
If the wind is blowing a certain way, the warm air starts spinning as it rises. If it spins fast enough, it takes on a funnel shape. That’s when it’s called a funnel cloud. Funnel clouds don’t touch the ground, but they can
still be dangerous. That’s because of their high winds. When a funnel cloud does touch the ground, it becomes a tornado.
Storm clouds are dark because of all the water in them. Tornadoes are dark for the same reason. Water is not all that’s in tornadoes. They also pick up dust, tree branches, pieces of objects that are destroyed, and other things. Red tornadoes happen in some parts of the United States. They turn red because of the red dirt that they pick up. Red tornadoes occur mostly in Oklahoma and Kansas, where the soil is often red.
It’s very hard to tell if a thunderstorm will create a tornado. Meteorologists, however, look for certain signs. One sign is what is called a wall cloud. This is a cloud that drops down from a band of clouds and moves
toward the ground.
When a tornado forms, it’s almost impossible to tell exactly what path it will take. But the scientists who are
storm chasers are learning more and more.
These scientists usually don’t see a tornado doing damage. That’s because they try to stay ahead of the
storm, not behind it. That’s not always easy because of the directions of the roads. But tornadoes usually are not very fast. Meteorologists estimate that most tornadoes travel at about 35 miles per hour (55 kilometers per hour). Storm chasers usually can drive faster than that.
Storm chasers often do see the destruction a tornado causes. One storm chaser who was a photographer saw a house that had nothing left but a bathtub, a toilet, and one wall. A neighbor told him that the family survived by “getting in the tub and covering up.”
Meteorologist Howard B. Bluestein is one of the leading tornado experts in the United States. He has described how a tornado once picked up a cottage with two people in it. The storm carried the cottage through the air and dropped it in a lake. The people inside then swam to the shore.
The Tri-State Tornado
One of the most terrible tornadoes in U.S. history was the Tri-State Tornado of 1925. It cut a 219-mile (352-kilometer) path of destruction through the states of Missouri, Illinois, and Indiana.
It began near Ellington, Missouri, at around 1:00 P.M. on March 18. At least 11 people were killed in Missouri. At around 2:00 P.M. the tornado reached Illinois, where the worst damage was done. In the town of Gorham, most of the buildings were destroyed, and 37 people died. In Murphysboro, 234 people died. At a school
in DeSoto, 33 children died. The tornado then moved into Indiana at around 4:00 P.M. In Griffi n, Indiana, 150 homes were wrecked.
The tornado fi nally died out at around 4:30 in the afternoon. In all, the twister caused many millions of dollars worth of damage and killed almost 700 people.