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.
That's because most of the shots of the Martian surface returned so far by the high-resolution camera have been much more static (see some of the first color images released last year by HiRISE). But in this case billowing clouds of dust reveal active landslides at the base of a towering slope.
"It really surprised me," HiRISE team member Ingrid Daubar Spitale, of the University of Arizona in Tucson, said in a press release.
"It's great to see something so dynamic on Mars. A lot of what we see there hasn't changed for millions of years."
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.
"We don't know [yet] what set off these landslides," HiRISE collaborator Patrick Russell of the University of Berne, Switzerland, said in the release.
"We plan to take more images of the site through the changing Martian seasons to see if this kind of avalanche happens all year or is restricted to early spring."
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