Whirlwind
Definitions
- 1: a small rotating windstorm of limited extent
- 2a : a confused rush : whirl <a whirlwind of meetings>
- b : a violent or destructive force or agency
Description
A whirlwind is a weather phenomenon in which a vortex of wind (a vertically oriented rotating column of air) forms due to instabilities and turbulence created by heating and flow (current) gradients. Whirlwinds occur all over the world and in any season.
Whirlwinds are subdivided into two main types, the great (or major) whirlwinds and the lesser (or minor) whirlwinds. The first category includes tornadoes, waterspouts, and landspouts. The range of atmospheric vortices constitute a continuum and are difficult to categorize definitively. Some lesser whirlwinds may sometimes form in a similar manner to greater whirlwinds with related increase in intensity. These intermediate types include the gustnado and the fire whirl. Other lesser whirlwinds include dust devils, as well as steam devils, snow devils, debris devils, leaf devils, and shear eddies such as the mountainado and eddy whirlwinds.
Major whirlwinds last longer because they are formed from very powerful winds, and it is hard, though not impossible, to interrupt them. Minor whirlwinds are not as long-lived; the winds that form them do not last long, and when a minor whirlwind encounters an obstruction (a building, a house, a tree, etc.), its rotation is interrupted, as is the windflow into it, causing it to dissipate.[1]
