Ice Clouds over Vastitas - Sol 94 (GIF-Movie; credits: NASA)

Clouds scoot across the Martian Sky in a movie clip consisting of 10 frames taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander.
This clip accelerates the motion. The camera took these 10 frames over a 10-minute period from 14:52 to 15:02 M.LT. at the Phoenix Site during Sol 94 (Aug. 29), the 94th Martian day since landing.

Particles of water-ice make up these clouds, like ice-crystal cirrus clouds on Earth. Ice hazes have been common at the Phoenix site in recent days. The camera took these images as part of a campaign by the Phoenix team to see clouds and track winds. The view is toward slightly West of due South, so the clouds are moving Westward or West-NorthWestward.

The clouds are a dramatic visualization of the Martian Water Cycle. The water vapor comes off the North Pole during the peak of Summer. The Northern-Mars Summer has just passed its peak water-vapor abundance at the Phoenix Site. The atmospheric water is available to form into clouds, fog and frost, such as the Lander has been observing recently.