This image of the surface of Mars covers a location that has been captured several times by the HiRISE camera aboard NASA's Mars Reconnaissance Orbiter to look for changes in gullies. Changes have now been seen in many gullies on Mars, and show that these landforms are evolving rapidly. The timing of the changes is often in winter or early spring, suggesting that they are caused by the carbon dioxide frost that forms in and around most gullies every year.
HiRISE is one of six instruments on NASA's Mars Reconnaissance Orbiter. The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies, Boulder, CO. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.