Similar to tornadoes, dust devils are swirling columns of air that blow across flat,
dusty desert and prairie areas. When the ground absorbs the sunís rays, it heats the
ir located immediately above its warming surface, causing it to rise and expand. The
air swirls in a motion like water running down a drain, and is made visible to the dust
and sand that it sweeps up from the ground. Dust devils move zig-zag fashion across the
earth at speeds of four to five miles per hour. They can rise to heights of several
hundred feet, but are most commonly about 100 feet high. Dust devils are rather
short-lived and donít cause much damage, but on May 29, 1902, a large dust devil
collapsed buildings in Phoenix, Arizona (USA).
In another instance, red dust formed during droughts in North Africa are known to be
blown into the air, where it combines with moisture and falls as red rain in Miami
(USA), 4,000 miles away.