The word tornado derives from the Spanish word tornado, meaning "thunderstorm", which in turn was derived from the Latin word tonare, meaning, "To thunder". People also refer to tornadoes as twister, and the colloquial term cyclone.A tornado is an atmospheric phenomenon associated with very rough weather. The Encyclopedia of Meteorology defines it as "a violently rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform cloud, but not always visible as a funnel cloud". Thus, tornadoes refer to a vortex of wind in contact with both the ground and cloud base, and formed before the water vapor present in such winds condense into clouds. Tornadoes form from violent thunderstorms, usually the super cell variety of the thunderstorm and cause widespread destruction in the path it swirls.
[...] In the mid 1970s, the US National Weather Service (NWS) increased its efforts to train storm spotters to spot key features of storms that indicate severe hail, damaging winds, and tornadoes. REFERENCES Books and Articles "What is a tornado?” Cooperative Institute for Mesoscale Meteorological Studies. 2001-10-01. http://www.cimms.ou.edu/~doswell/a_tornado/atornado.html. Retrieved on 2009- 05-08. Edwards, Roger (2006-04-04). "The Online Tornado FAQ". Storm Prediction Center. http://www.spc.noaa.gov/faq/tornado. Retrieved on 2009-05-08. Encyclopedia Britannica. "Tornado: Global occurrence". http://www.britannica.com/eb/article-218357/tornado. Retrieved on 2009-05- 08. Forbes, Greg. "weather.com - Blog: The Weather Channel on weather news, hurricanes, tornadoes, & meteorology". http://www.weather.com/blog/weather/8_9262.html. Retrieved on 2009-05-10. Frederick C. Mish (1993). Merriam Webster's Collegiate Dictionary (10th ed.). Springfield, MA: Merriam-Webster, Incorporated. [...]
[...] However, thunderstorms and tornadoes are too small for the direct influence of the Coriolis Effect, and their rotation depends on complex processes within the thunderstorm and the ambient environment. Most tornadoes however rotate counterclockwise in the northern hemisphere, and clockwise in the southern hemisphere. Speed Most tornadoes have wind speeds between 40 mph (64 km/h) and 110 mph (177 and are approximately 250 feet (75 across, and travel a few miles before dissipating. Larger tornadoes however attain wind speeds of more than 300 mph (480 stretch more than a mile ( 1.6 km) across, and proceed along its path for many miles. [...]
[...] LIFE CYCLE OF TORNADOES Tornadoes grow in strength and intensity as long as it has a good source of warm, moist inflow of warm air. When the inflow of hot air peaks, the tornado achieves its mature state and cause maximum damage. This mature stage could last anywhere from a few minutes to more than an hour, depending on the warm air sucked up by the vortex. This stops when the downdraft, now an area of cool surface winds, begins to wrap around the tornado and cut off the inflow of warm air. [...]
[...] ISBN 0-87779-709-9. http://www.merriam-webster.com/dictionary/tornado. Golden, Joseph. "Waterspouts are tornadoes over water". USA Today. http://www.usatoday.com/weather/wspouts.htm. Retrieved on 2009-05-09. Grazulis, Thomas P.; Flores, Dan (2003). The Tornado: Nature's Ultimate Windstorm. Norman OK: University of Oklahoma Press. pp ISBN 0-8061- 3538-7. http://www.srh.noaa.gov/mfl/hazards/info/waterspouts.php. Retrieved on 2009-05-08. Harper, Douglas (November 2001). "Online Etymology Dictionary". http://www.etymonline.com/index.php?term=tornado. [...]
[...] Dust devils differ from tornadoes in the sense that they form from the ground and work their way upwards. They form when intense heat of the sun a layer of air just above the ground to heat up rapidly and rise. When cool air tries to fill the space left by the rising warm air, the warm rising air starts to spin, with the speed of the spin depending on how fast the warm air rises. Such dust devils rotate either clockwise or anti0clockwise depending on the local topography that affects wind flow. [...]
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