March 8, 2012 — The wispy white plume of a dust devil snakes half a mile above the surface of Mars in this stunning image, captured by the HiRISE camera aboard NASA's Mars Reconnaissance Orbiter on Feb. 16, 2012.
Created by rapidly rising air above the warm Martian surface, the dust devil appears to be moving southeast and has left a bright trail behind it on the ground — despite the easterly direction of its plume, which is being sculpted by a breeze about 250 meters up.
Although the air on Mars is very thin by Earthly standards, it can still carry dust aloft when conditions are right.
As spring progresses in Mars' northern hemisphere, increased solar energy heats the surface and creates rising columns of warm air. These columns pick up the fine Martian soil and carry it along with the prevailing wind, leaving bright or dark trails in their wakes depending on the underlying material.
Dust devils have been spotted many times before on Mars, both from orbit and from the ground. Click here to see a rover's-eye-view of other devils in action!
-- by Jason Major.