When dust is picked up by the swirling air, a dust devil is seen. They are like mini-tornadoes, but with important differences. Tornadoes pack winds of up to 300 miles per hour. A dust devil spins at only 30 to 70 m.p.h. Tornadoes develop underneath thunderstorms.
Dust devils form when the weather is clear, hot, and dry.
Sometimes, a dust devil picks up more than sand. According to Szumowski at the Desert Research Institute, dust devils may also suck up flames from a nearby forest fire. According to Dr. Sisterson at the Argonne National Laboratory, the answer was thought to be the top of the troposphere. That's about 12 miles up. But after some dramatic discoveries in the last 10 years, that answer has been revised.