Dust devil, Arizona, USA. This is a type of small, weak tornado that commonly occurs in hot, dry areas. It is usually formed when winds are deflected by terrain features into a rotating column. If updrafts caused by heating of the surface are also present, then a dust devil can form. The updraft and rotation pull dust from the surface, making the funnel visible. A dust devil is not as destructive or large as a tornado, and poses little threat.