Mars’ northern-most sand dunes are beginning to emerge from their winter cover of seasonal carbon dioxide (dry) ice. Dark, bare south-facing slopes are soaking up the warmth of the sun.
The steep lee sides of the dunes are also ice-free along the crest, allowing sand to slide down the dune. Dark splotches are places where ice cracked earlier in spring, releasing sand. Soon the dunes will be completely bare and all signs of spring activity will be gone.
Written by: Candy Hansen (audio: Tre Gibbs) (5 March 2014)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_035033_2635
Image: NASA/JPL/University of Arizona