Tornadoes are also called twisters, and the wind speed of extreme tornadoes can reach up to 300 miles per hour. The United States averages 1,200 tornadoes each year, which is more than any other country. Tornadoes that take place above water are called waterspouts. Most tornadoes occur in a region called Tornado Alley; Kansas, Oklahoma, Texas and Florida are U.S. states where tornadoes occur most often.
A tornado is a violent rotating column of air that is in contact with the earth's surface and a cumulonimbus cloud or, in some instances, the base of a cumulus cloud. Extreme tornadoes that reach up to 300 miles per hour can be two miles wide and stay on the ground for more than 100 miles. A waterspouts is described as a funnel-shaped wind current connected to a cumulonimbus or cumulus cloud, and they typically develop in tropical areas near the equator. Some people have storm shelters at their homes to stay underground when there is a tornado.
In 1925, Annapolis, Missouri was hit by one of the worst tornadoes in history. Passenger trains were turned over, cars were carried above rooftops, stone buildings were ruined, 823 people were killed and almost 3,000 people were injured.