The tornado is a powerful, twisting windstorm. The winds of a tornado are the most violent winds that occur on the earth. They whirl around the center of the storm at speeds of more then 200 to 300 miles (320 to 300 kilometers) per hour. Most tornadoes measure several hundred yards or meters in diamerter, and many have caused widespread death and destruction. A tornado is a rotating funnel cloud that extends down from a dark mass of clouds. Some of the funnels don't reach the earths surface. Others may strike the surface of the earth, withdraw into the dark clouds above, and then dip back down and strike the earth again. A tornado strikes with terrible force. Its violent winds can destroy buildings, uproot trees, and carry automobiles and other large objects great distances. A tornado can flatten a town or city in no time at all. In the United States, most funnel clouds tend to travel toward the northeast. Most tornadoes last less then one hour. These tornadoes travel about 20 miles (32 kilometers) at a speed of 10 to 25 miles (16 to 40 kilometers) per hour. However, some tornadoes last several hours and measure up to one and a half miles (2.4 kilometers) in diameter. These may travel 200 miles (320 kilometers) or more at up to 60 miles (97 kilometers) per hour. Such tornadoes are especially destructive. There are between 800 to 900 tornadoes reported each year in the United States.

            First, a dence, dark cloud forms. Rotating air at the bottom of the cloud then forms into a narrow cloud called a funnel. Then, the funnel extends toward the surface. If the funnel touches the surface, it raises a huge dust cloud, and destroys almost everything in its path.
 
 

          Always open a window during a tornado.  A storm cellar is thebest protection against a tornado. A basement is the next best place to take shelter. In a basement, people should crouch under a table at the opposite side of the room that the tornado is approaching. In a building that has no basement, they should lie face down under a table or a bed on the ground or floor, away from any windows. Mobile homes should always be vacated if a tornado is approaching. They offer almost no protection and can easily be overturned by a tornado. Outside, people should lie face down in a ditch or a ravine if possible. This action would provide some protection against flying debris but wouldn't prevent a tornado from lifting a person into its funnel.