The force of the earth's rotation gets the air spinning. 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.