Artwork of dust devils on the surface of Mars. Dust devils are tall and short-lived whirlwinds. They form when a pocket of hot air near the surface rises quickly through cooler air above it to create an updraft of rotating air. Dust devils were first seen on Mars in the 1970s by the Viking probes, and are a well-documented phenomenon. They tend to be substantially larger than those on Earth, up to about 2 km in height, although the ones depicted here are only a few metres tall.