Tornado warning
From Freepedia
See Severe weather terminology for a comprehensive article on this term and related weather terms.
A tornado warning is issued when:
- a tornado is reported on the ground,
- a funnel cloud is reported in the sky,
- a waterspout is headed toward landfall, or
- a thunderstorm with strong rotation is indicated by doppler radar.
A tornado warning means there is immediate danger for the warned area -- if not from the relatively narrow tornado itself, from the severe thunderstorm producing (or likely to produce) it. Everyone in the path of such a storm is advised to take cover immediately, as it is likely a life-threatening situation.
In the United States, the National Weather Service issues warnings for tornados and severe thunderstorms on a per-county basis, although warnings may only be issued for portions of counties depending on the size and track of the cells.
Advances in technology, both in indentifying conditions and in distributing warnings effectively, have been credited with reducing the death toll from tornados. The average warning times have increased substantially; in some cases to more than a half hour's warning of impending tornados. The U.S. tornado death rate has declined from 1.8 deaths per million people per year in 1925 to only 0.11 per million in 2000. Much of this change is credited to improvements in the tornado warning system.
A warning must not be confused with a tornado watch which only indicates that conditions are likely to produce a tornado.
