Click for full image.

Cool image time! The photo to the right, cropped to post here, was taken on September 18, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows a very distinct impact crater on top of the layered deposits of ice mixed with dirt that form the bottom layers as well as surround the visible north pole ice cap on Mars.

I purposely cropped the high resolution image so that the crater is off center to show the dark streaks that appear to blow away from the crater to the northwest, west, and southwest. This asymmetric pattern suggests the wind direction at this location generally flows to the west, but the pattern might also be caused by lighting effects. The location is at 82 degrees north latitude, and the Sun was only 31 degrees high when the picture was taken, causing long shadows. Also, in the full image, you can see a whole strip of similarly oriented streaks, suggesting that these are slope streaks descending a slope going downhill to the northwest.

The overview map below also provides important information about this location.

The yellow cross indicates the location of this small 500-foot-wide crater. For most of the ice cap, the descent down from the icy upper layers (generally green on the map) to the dirtier layered deposits (trending to blue on the map) is steep and abrupt, a cliff where orbital images routinely capture avalanches in the spring, as they occur. At this location however that slope going down to the west is more gentle, with only a few relatively small and gentle steps downward. This crater happens to be located along one of those steps, which might explain the northwest pointing streaks.

Note that the ice in the crater might not be water ice. At this latitude each winter a mantle of dry ice snow covers everything, only to sublimate away when the Sun arrives in the spring. It is possible that this ice is dry ice that has not yet disappeared.