This HiRISE image is of a region east of the Hellas impact basin and south of Reull Vallis. Unexpectedly, HiRISE caught a dust devil blowing across the Martian surface in the southwest portion of the image.

Dust devils form when the temperature of the atmosphere near the ground is much warmer than that above. The hot air rises, and under ideal conditions, forms a vortex that sucks in more warm air. If the vortex is strong enough, it will raise dust off the surface, forming a dust devil.

Dust devils generally form in the afternoon because the sunlight needs sufficient time to warm the surface. When this image was taken, the local time was about 3:08 p.m. In addition to the main image, we show here a small version of the HiRISE image with an arrow showing the location of the dust devil (364 x 800; 284 KB). The third subimage shows the dust devil close up (1294 x 822; 1 MB).

The bright material is the dust within the vortex, and a dark shadow cast by the dust devil is visible to the right. The diameter of this dust devil is about 200 meters, but at the surface it is probably much smaller. Based on the length of the shadow in this image, the dust devil is on the order of 500 meters tall.
Written by: Nathan Bridges

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible: Image: NASA/JPL/University of Arizona

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.