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Tornado season has started in the United States. Recently, a series of storms blew across the Dallas – Fort Worth area in Texas. The tornadoes damaged or destroyed hundreds of homes.
A tornado is a fast-turning tube of air which ‘’hangs’’ from a thick cloud. It extends from a thunderstorm in the sky down to the ground. The shape is like a funnel: wide at the top, narrower at the bottom.
Tornadoes form when winds, which blow in different directions, meet in the clouds and begin to turn in circles. Warm air, which rises from below, causes the wind tube to reach toward the ground. Because of their circular movement, these windstorms are also known as twisters.
The most severe tornadoes can reach wind speeds of 320 kilometers an hour or more. In some cases, the paths of damage can stretch more than a kilometer wide and 80 kilometers long.
With a tornado, bigger does not always mean stronger. Large tornadoes can be weak. And some of the smallest tornadoes can be the most damaging. They can carry trees, cars or homes from one place to another. They can also destroy anything in their path.
Tornadoes have been observed on every continent except Antarctica. But experts say they are most often seen in the United States. On average, there are more than 1,000 nationwide each year. Tornadoes kill 70 people and injure 1,500 others nationwide in an average year.
Tornadoes are observed most often in the middle of the United States, where the land is mostly flat. Tornadoes can happen any time of the year. But most happen from late winter to the middle of summer. In some areas, there is a second season in the fall.
Most injuries happen when flying objects hit people. Experts say the best place to be is in an underground shelter, or a small, windowless room in the lowest part of a building.
People who drive during a tornado are told to find low ground and lay flat, facedown, with their hands covering their head. People in the path of a tornado often just have minutes to make life-or-death decisions.
In April 2011, the country broke a 37-year-old record for the largest tornado outbreak. A ‘’tornado outbreak’’ is often defined as six or more tornadoes happening within a day.