A tornado (the Spanish tornado , derived from the verb tornar turn) is a vortex ( whirlpool ) of winds extremely violent, begin to cloud base of a thunderstorm ( cumulonimbus ) when the conditions of wind shear are favorable in the lower atmosphere . Very weak tornadoes may also develop under clouds of rain ( cumulus ).
This phenomenon weather has a destructive power than a tropical cyclone in meter square, but is of limited duration and scope: it provides a corridor several hundred meters wide and several kilometers long. Some tornadoes spawned the winds strongest reported to the surface of the globe . They kill each year 300 to 400 people (according to an estimate of the World Meteorological Organization ), 150 U.S.
A tornado (from Spanish tornar to German "repent, turn, (to) turn", from the Latintornare , with the same word meaning ), also Großtrombe , wind- or water-spout , colloquially in the United States Twister called, is a small-scale vortices in the Earth's atmosphere , of an approximately vertical axis of rotation and having associated with convective clouds ( cumulus and cumulonimbus ) is what the difference to whirlwind accounts (dust devils). The vortex in this case extends continuously from the ground to the cloud base. This definition goes on Alfred Wegener back (1917) and is still widely accepted in this form today.
The terms wind- and water-spout ( engl. : Waterspout ) denote the German language area a Großtrombe (Tornado in the broader sense) over land or larger bodies of water (sea, large inland lakes). tornado is a synonym for a tornado in the narrower sense, ie about country.
The term "wind pants" - in the older literature yet well defined (Wegener) - was increasingly undifferentiated used in the recent past for various phenomena related to sudden strong winds (for example, downburst ) or falsely based on whirlwind. In addition, the impression of a difference between "big" tornadoes in North America and "small" wind pants in Europe was awakened. One difference between whirlwinds and tornadoes However, neither in terms of their physical nature nor with regard to their strength