Back

WEATHER
Lesson 5 - Page 3

Next 

A severe thunderstorm may spawn a tornado, a violently rotating column of air which descends from a thunderstorm cloud system. The winds of a tornado are the most violent winds that occur on the Earth, reaching speeds of up to 300 mph. It extends down from a mass of dark clouds as a whirling funnel and moves over land in a narrow path. On the average, tornadoes move about 30 miles an hour, however, some move very slowly while other speed along at 60 miles an hour or more. Tornadoes generally rotate counterclockwise in the northern hemisphere, and clockwise in the southern hemisphere.

Tornadoes usually last less than an hour, traveling distances of about 20 miles. Tornadoes occur throughout the world, but mostly in the central United States in what is called "Tornado Alley" during the spring and summer.

   Back

[Back to Weather]  [Back to Earth Science Grid]

Next