The phenomenon of dust devils on the Martian surface has been known for year but the best image of one was recently taken by NASA's High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.
Dust Devils are spinning columns of air that pull dust from the surface to form a column. They are similar to a tornado on Earth but they differ because they are usually developed on a clear day when the sun warms the ground and air directly above. Then the warmer air rises through a small pocket of cooler air and may begin to rotate. Dust Devils occur on Earth, too.
This twister is about a half a mile tall.
Credit: NASA/JPL-Caltech/Univ. of Arizona