It is now fall in the southern hemisphere and in the giant impact crater known as Hellas basin small boulders cast long shadows. The long shadows emphasize small scale topographic features. Wind erosion is responsible for much of the morphology in this region.

Frost is condensing, and shows up as bright blue patches in this false color image. This is seasonal carbon dioxide frost. Closer to the pole, carbon dioxide condenses from the atmosphere and forms a seasonal polar cap. At this latitude we do not expect a thick layer to form but rather the frost collects in cold protected areas on poleward-facing slopes.

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.