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Dust Devils on Mars
This cliff is the site of the most frequent frost avalanches seen by HiRISE.
09.30.2015

Avalanche Ho!

This cliff is the site of the most frequent frost avalanches seen by HiRISE. In this area in northern Spring, frost avalanches are common and HiRISE monitors this cliff, or scarp, to learn more about the timing and frequency of the avalanches, and their relationship to the evolution of frost on the flat ground above and below the scarp. These avalanches remind us, along with active sand dunes, dust devils, slope streaks and recurring slope lineae, that Mars is an active and dynamic planet.

The small white cloud in front of the brick red cliff is likely carbon dioxide frost dislodged from the layers above, caught in the act of cascading down the cliff. It is larger than it looks, more than 20 meters across, and it probably kicked up clouds of dust when it hit the ground. The avalanches tend to take place when the North Polar region is warming, suggesting that the avalanches may be triggered by thermal expansion.

Image Credit: NASA/JPL-Caltech/University of Arizona

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