This image covers Raga Crater, the location of well-studied recurring slope lineae (RSL). RSL are dark flows that disappear and re-form every Mars year at certain locations.

A closeup image compares the dark flows at the same time in three consecutive Mars years. We can see that the pattern of lineae is nearly the same every year, but in the latest image they are slightly shorter.

Comparisons like these will help the HiRISE team learn how much the flows vary from year to year, as well as why they are different.

Written by: Colin Dundas (audio by Tre Gibbs)   (11 March 2015)

More info and image formats at http://hirise.lpl.arizona.edu/ESP_040028_1315

Image: NASA/JPL/University of Arizona