This movie clip shows some distant dust devils and one closer one blowing across the floor of Mars' Gusev Crater. It consists of frames taken by the navigation camera on NASA's Mars Exploration Rover Spirit during the rover's 537th martian day, or sol (July 7, 2005).
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.
In this clip, contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust moved by wind. The total time elapsed during the taking of these frames was 13 minutes, 46 seconds.