When frozen carbon dioxide - dry ice - is mixed in with sand and rock on Mars, it can disturb the ground around it when it warms up. And that means cliffs on the Red Planet are dangerous places to be in spring time: avalanches like this one are common!
The Mars Reconnaissance Orbiter's HiRISE camera has spotted quite a few of these avalanches, and they're awesome each time. In this event you can see the white plume of dry ice and sand falling down the cliffside, and the huge billowing plume of dust where it hits. Look at it: you're seeing a gigantic landslide caught in the act! And the only reason I didn't pick this one for my Top 14? Because another one made my list in 2008
. Get the hi-res version here.Image Credit: NASA/JPL/University of Arizona