[*True Waterspouts= Develop at the base of congestus clouds and move downwards. These whirlwinds form when a center of low air pressure develops. This low air pressure causes winds to whirl forming the waterspout. They rarely exceed 50mph and usually lasts less than 15 minutes. Waterspouts can gain a height, anywhere from a few hundred to several thousand feet.
*Fair Weather Waterspouts= These are whirling columns of water droplets that spiral up from a lake or sea. These waterspouts frequently form under clear skies. The abundance of moisture that is present, for this whirlwind, generally form small cloud and sometimes a thunderstorm develops.]
[*These are not true tornadoes. They are formed in intense heat such as forest-fires. They are found spinning out of these intense heat conditions.]
[*Within the outflow of air, from severe thunderstorms, Gustanadoes are sometimes formed. The top wind of this whirlwind may reach 150mph. and these storms rarely last about 5 minutes.]
[*Another name for this whirlwind is the miniature twister. *These are generally seen by volcanoes. The convection currents from the heat of the eruptions sometimes causes this whirlwind.]
[*These whirlwinds are formed the same way as gustnadoes, but are a little stronger. They are stronger than gustnadoes in that the winds may reach 175mph(F2) and they last longer than 5 minutes.]
[*These are small rotating columns of air. They are seen picking up leaves and twirling them around a few times.]
[*Other names are snow spouts and snow whirlies.
*Meteorologists have just begun to look at this form of whirlwind. Some suggest that they may simply be wind eddies from physical obstructions or by gusty winds.]
[*Also named Cold Air Funnels and Cold tornadoes.
*These whirlwinds are spawned by storms that are not considered severe and within an area with cold and unstable air mass present.]
[*This is the most damaging of whirlwinds. A Tornado is a rapid rotating column of air that comes down from the base of a
cumulonimbus cloud to the ground. The color of the tornado is attributed to what substance the cloud is in contact with. For
instance, if the cloud crosses over red sand then the tornado will take on a reddish hue. These storms are the result of
clashing warm and cold air currents that lead to instability of the atmosphere
and great turbulence. These storms travel
around 10-30mph and generally follow a Northeasterly path. The width of the vortex may range anywhere from a few yards to
several hundred yards. These storms usually last less than an hour, these unpredictable storms may last up to several hours.
[Sources: The information above was found using many references these include:
The World Book Encyclopedia 1998, Encarta 1994, The American Peoples Encyclopedia
National Audubon Society Field Guide to North American Weather
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