Dust devils are usually harmless, but can on rare occasions grow large enough to pose a threat to both people and property.

Dust devils form as a swirling updraft under sunny conditions during fair weather, rarely coming close to the intensity of a tornado.

The secondary flow in the dust devil causes other hot air to speed horizontally inward to the bottom of the newly forming vortex.

[3] A dust devil, fully formed, is a funnel-like chimney through which hot air moves, both upwards and in a circle.

Usually it occurs when the dust devil is moving slowly (depletion) or begins to enter a terrain where the surface temperatures are cooler.

Many dust devils are usually small and weak, often less than 3 feet (0.9 m) in diameter with maximum winds averaging about 45 miles per hour (70 km/h), and they often dissipate less than a minute after forming.

On rare occasions, a dust devil can grow very large and intense, sometimes reaching a diameter of up to 300 feet (90 m) with winds in excess of 60 mph (100 km/h+) and can last for upwards of 20 minutes before dissipating.

Based on the degree of damage left behind, it is estimated that the dust devil produced winds as high as 75 mph (120 km/h), which is equivalent to an EF0 tornado.

[10] On May 19, 2003, a dust devil lifted the roof off a two-story building in Lebanon, Maine, causing it to collapse and kill a man inside.

[11][12] On June 18, 2008, a woman near Casper, Wyoming was killed when a dust devil caused a small scorer's shed at a youth baseball field to flip on top of her.

One case occurred in Engebæk, Billund Municipality, Denmark in 1868 where a dust devil tossed tuft into a heater, causing a wildfire that possibly extended from 10,000 to 50,000 hectares or more.

They were discovered from data reported by NASA's Viking probes, and have been photographed by orbiting satellites and surface rovers in subsequent missions.

[30][31] Hot cinders underneath freshly deposited ash in recently burned areas may sometimes generate numerous dust devils.

The lighter weight and the darker color of the ash may create dust devils that are visible hundreds of feet into the air.