Whirlwinds are similar to tornadoes, but are decidedly smaller and with less energy. When they evolve from storm clouds, they behave like small tornadoes and can be quite destructive. Whirlwinds, also called dust devils, with smaller dimensions and minor energy, usually form in very warm and dry air conditions in desert regions or in the plains and are not associated with clouds or precipitation. These vortices are triggered off by convective phenomena caused by intense heating of the ground. ‘Dry’ whirlwinds of this kind are very frequent in the SW of the United States, where generally their size is limited, and they cause no damage. A game that  American children living in this area often play, is to try and chase the whirlwind and enter inside the vortex: when they succeed in doing this the convective process gets interrupted and the whirlwind vanishes.

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