Martian Avalanche: First Photos

"Avalanche Photographed on Mars " Space.com (March 3, 2008)

What's special here is that the avalanched was photographed while it was happening.

"A NASA spacecraft has taken the first-ever image of an avalanche in action near Mars' north pole.

"The High Resolution Imaging Experiment (HiRISE) on NASA's Mars Reconnaissance Orbiter took the photograph Feb. 19. The image, released today, shows tan clouds billowing away from the foot of a towering slope, where ice and dust have just cascaded down."

There's a set of four photos, displayed on a link from that page.