Today's Images of Mars come from HiRISE and show two avalanches in the North Polar Region of Mars! The HiRISE team was kind of enough to outline all of them in their collection of images from 2008. The left images show the context for the avalanche and outlines what area the image to the right will show.
The dust clouds produced by the avalanches can be huge! The one shown in the top image measured about 180m in diameter and extends around 190m from the base of the cliff. The shadows to the lower left of each image indicate that these are dust clouds and not just a strange feature on the surface.
The particular cliff imaged here is over 700m tall and has slopes of over 60 degrees in some areas. The top left of these images shows the carbon dioxide frost that still covered the top of the scarps.
It is important that we learn how and why these geological processes work so that we can get an accurate picture of how Mars has evolved and what it looked like in the past. If we better understand the past environment on Mars we can better determine if Mars was once a planet more hospitable to life and we can use that information to determine what the environment on Mars is now and will become.
Clicking on these images will take you to the original high resolution images from HiRISE. [See their caption for the images]