A tornado forms when the warm air rises above the cold and twists into a funnel-shaped cloud. This is why tornadoes are sometimes called twisters. Funnel clouds can drop out of thunderstorms with little or no warning. These snake-like clouds extend down and sometimes touch the ground. When they do touch down, they can cause damage.
Tornado funnels act like big vacuum cleaners.
Tornadoes pick up dirt, trees, buildings and everything else that their violent winds destroy. Tornado wind speeds can reach 300 miles per hour. No other winds blow that fast. The winds are so powerful that they can drive a piece of straw right through a board. The Fujita Scale relates wind speed to how much damage a tornado causes.