| Revision as of 15:57, 29 April 2003 view sourceEgil (talk | contribs)Administrators20,816 edits Put image in diversion, moved attribution to image description← Previous edit | Revision as of 01:05, 5 May 2003 view source Minesweeper (talk | contribs)Administrators16,385 edits fmNext edit → | ||
| Line 1: | Line 1: | ||
| ] ] | ] ] | ||
| <div style="float:right; |
<div style="float:right; margin-left:1em; text-align:center"> | ||
| ] | ]<br>] | ||
| </div> | </div> | ||
Revision as of 01:05, 5 May 2003
A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud.
It is spawned by a thunderstorm (or sometimes as a result of a hurricane) and produced when cool air overrides a layer of warm air, forcing the warm air to rise rapidly. The damage from a tornado is a result of the high wind velocity and wind-blown debris. Tornado winds range from a slow 40 mph at the low end to a possible 300 mph in the strongest storms. Tornado season in North America is generally March through August, although tornadoes can occur at any time of year. They tend to occur in the afternoons and evenings: over 80 percent of all tornadoes strike between noon and midnight.
Tornadoes can be nearly invisible, marked only by swirling debris at the base of the funnel. Others are composed of several mini-funnels. A tornado must by definition have both ground and cloud contact.
Tornadoes do occur throughout the world. However, the United States experiences by far the most tornadoes of any region of comparable size, and has also suffered the most intense ones. On average, the United States experiences 100,000 thunderstorms each year, resulting in over 1,000 tornadoes and approximately 50 death per year. The deadliest US tornado on record is the 18 March 1925 Tri-State tornado that went across southeastern Missouri, southern Illinois, and southern Indiana, killing 695 people.
The intensity of tornadoes is measured by the Fujita - Pearson Tornado Scale (also known simply as Fujita scale).
See also: Tropical cyclone, curl
Tornado is also:
- The name of a class of sailboat.
- The name of two military aircraft, the current Panavia Tornado and the WW II non-production Hawker Tornado