A tornado is a very intense local storm with a fierce swirling motion of air, forming a dark writhing column called a funnel that hangs from black clouds. The rotational speed of the wind in the funnel has been estimated to reach 300 mph and occasionally 500 mph. Unlike gales, which often sweep across thousands of miles of land and sea, tornadoes are rarely more than a few 100 yards wide and often less. Tornadoes, also called twisters or whirlwinds, are short lived and the majority travel only about 10-20 miles at speeds of approximately 40 mph.

 A tornado is a vortex. It is something like the minor whirlwind sometimes formed where winds meet at street corners except that in a tornado there is a strong upward motion instead of a downward flow. The tornado funnel is hollow. Its dark appearance is caused partly by dust that is sucked up and partly by water droplets that condense from the air as it rises up the funnel. The upward motion of the air means that near the ground there must have been initially a layer of warm moist air with a deep layer of cold drier air above. Before the tornado forms the weather is usually oppressive and the sky has a threatening appearance very much like that before a thunderstorm which sometimes precedes a tornado.

It is impossible for meteorologists from an inspection of a weather map to predict exactly when and where a tornado will strike. Many tornadoes travel slowly when the funnel touches the ground. When the funnel is entirely in the air there is a loud buzzing sound. Once the funnel reaches the ground the sound changes to a loud roar and the fierce winds hurl stones trees and anything that lies in their path into the air. Tornadoes are extremely destructive because of the concentration of the energy released by the condensation of water vapour in a very small volume. The swirling motion creates very low pressure at the core of the funnel. As the funnel sweeps over building the pressure of the air trapped inside often cause it to burst.

The tremendous force of the wind completes the destruction. The damage caused by a tornado is sometimes worsened by the lightning and hail that frequently accompany tornadoes. It is not know whether tornadoes can be prevented or dispersed. Safety first is therefore the best rule. The only safe place in a tornado is a deep cellar or basement or the interior part of a home or building-a closet, bathroom or hall on the lowest floor.