TODAY'S THEMIS IMAGE: Winter in Hellas Basin (I'm surprised they didn't call it "Hellas Frozen Over"):

Right now on Mars it is winter in the southern hemisphere. This means that the usually cloudy Hellas Basin is relatively free from clouds. Even though there is little cloud cover, the atmosphere is still much thicker due to the depth of the basin than elsewhere on Mars, making image details not a crisp as when viewed through lesser amounts of atmosphere. In the center of the image are several dark streaks which originate from the side of a higher standing butte. The dark material is likely being eroded from a single layer within the cliff face. Wind has moved some of the eroded dark material to form the streaks.