a small-diameter columnar vortex of rapidly swirling air. A broad spectrum of vortices occurs in the atmosphere, ranging in scale from small eddies that form in the lee of buildings and topographic features to fire storms, waterspouts, and tornadoes. While the term whirlwind can be applied to any atmospheric vortex, it is commonly restricted to atmospheric systems that are smaller than tornadoes but larger than eddies of microscale turbulence. The generic whirlwind is usually modified to reflect the visible features associated with the whirl; thus there are dust whirls or dust devils, sand whirls or sand pillars, and fire, smoke, snow, and even hay whirls.