A tornado is a violently rotating column of air extending from a thunderstorm base to the ground with concentrated, whirling debris or a dust cloud. (A funnel cloud rotates, but has no contact with the ground, no debris and is not doing any damage).
- Tornadoes usually are preceded by very heavy rain and, possibly, hail. If hail falls from a thunderstorm, it is an indication that the storm has large amounts of energy and may be severe. In general, the larger the hailstones, the more potential for damaging thunderstorm winds and/or tornadoes.
- The most violent tornadoes are capable of tremendous destruction, with wind speeds of 250 m.p.h. or more.
- An average tornado damage path is one-to-two miles long, but can be in excess of one mile wide and 50 miles long.
- Widths vary considerably during a single tornado, from less than ten yards to more than a mile, but typically are about 50 yards wide.
- The average tornado moves from southwest to northeast, though tornadoes have been known to move in any direction.
- The average forward speed of a tornado is 30 m.p.h. but may vary from nearly stationary to 70 m.p.h.
- Tornadoes are most likely to occur between 3 p.m. and 7 p.m. but have been known to occur at all hours of the day or night.
- The National Weather Service uses Doppler weather radar to sense the air movement within thunderstorms. Early detection of increasing rotation aloft within a thunderstorm can allow time for lifesaving warnings before the tornado forms.
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« this page last modified 05/01/06 »
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