Tornado
From the Simple English Wikipedia, the free encyclopedia that anyone can change
A tornado is a tube of spinning air that touches the ground. Wind inside the tornado, spinning very fast, makes tornadoes very dangerous.
Tornadoes mostly happen during very strong thunderstorms called supercell storms. They cause a lot of damage to anything they touch. People die every year from tornadoes.
Tornadoes are ranked on the Fujita scale, from F0 to F5. F0 has the lowest wind speed, and F5 has the highest wind speed.
The United States of America has the most tornadoes every year, but tornadoes can happen in any country. If a tornado is coming, the safest thing to do is go to a basement or a bathroom with no windows. People should never be in a car or a mobile home when there is a tornado near.
[change] Classifications
- Tornado
- A tornado is defined by the Glossary of Meteorology as "a violently rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud..."[1]
- Condensation funnel
- A tornado is not necessarily visible; however, the intense low pressure caused by the high wind speeds (see Bernoulli's principle) and rapid rotation (due to cyclostrophic balance) usually causes water vapor in the air to condense into a visible condensation funnel. The tornado is the vortex of wind, not the condensation cloud.
- A funnel cloud is a visible condensation funnel with no associated strong winds at the surface. Not all funnel clouds evolve into a tornado. However, many tornadoes are preceded by a funnel cloud as the mesocyclonic rotation descends toward the ground. Most tornadoes produce strong winds at the surface while the visible funnel is still above the ground, so it is difficult to tell the difference between a funnel cloud and a tornado from a distance.
- Tornado family
- Occasionally, a single storm produces multiple tornadoes and mesocyclones. This process is known as cyclic tornadogenesis. Tornadoes produced from the same storm are referred to as a tornado family. Sometimes multiple tornadoes from distinct mesocyclones occur simultaneously.[2]
- Tornado outbreak
- Occasionally, several tornadoes are spawned from the same large-scale storm system. If there is no break in activity, this is considered a tornado outbreak, although there are various definitions. A period of several successive days with tornado outbreaks in the same general area (spawned by multiple weather systems) is a tornado outbreak sequence, occasionally called an extended tornado outbreak.[1][3]
[change] References
- ↑ 1.0 1.1 Glossary of Meteorology, Second Edition. American Meteorological Society (2000). Retrieved on 17 November 2006.
- ↑ Branick, Michael (2006). A Comprehensive Glossary of Weather Terms for Storm Spotters. NOAA. Retrieved on 27 February 2007.
- ↑ Russell S. Schneider; Harold E. Brooks, and Joseph T. Schaefer (2004). Tornado Outbreak Day Sequences: Historic Events and Climatology (1875–2003) (PDF). Retrieved on 20 March 2007.
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