First Mars Avalanches Seen In Action

clipped from news.nationalgeographic.com March 3, 2008—The first-ever picture of avalanches occurring on Mars might have had scientists yodeling for joy when they found it among the latest batch of images from NASA's orbiting HiRISE camera. The action took place along a stretch of cliff that stands about 2,300 feet (700 meters) tall and slopes in places by more than 60 degrees. The cliff borders the dome of layered deposits that sits atop the red planet's north pole. At the top of the cliff (left) sit layers of carbon dioxide frost that are now in retreat as Martian spring gets into gear. The bulk of material that cascaded off the slope is probably made up of fine-grained ice and dust, the researchers say, although it might include a few large chunks of debris.