Dust Devil in GusevThis image shows several dust devils moving from right to left across a plain inside Mars' Gusev Crater, as seen from the vantage point of NASA's Mars Exploration Rover Spirit in hills rising from the plain. The image was taken by Spirit's navigation camera during the rover's 543rd martian day, or sol (July 13, 2005). For a movie clip of the dust devils see: http://photojournal.jpl.nasa.gov/catalog/PIA04157
Spirit began seeing dust devil activity around the beginning of Mars' spring season. Activity increased as spring continued, but fell off again for about two weeks during a dust storm. As the dust storm faded away, dust devil activity came back. In the mid-afternoons as the summer solstice approached, dust devils were a very common occurrence on the floor of Gusev crater. The early-spring dust devils tended to move southwest-to-northeast, across the dust devil streaks in Gusev seen from orbit. Increasingly as the season progresses, the dust devils are seen moving northwest-to-southeast, in the same direction as the streaks. Scientists are watching for the big dust devils that leave those streaks.
Image Credit: NASA/JPL-Caltech/Texas A&M/Cornell