A Mars Express red planet flyover

From Phil Plaits description:

I was also intrigued by a crater shown at the 1:50 mark, which looks like it got filled by a landslide off a nearby hill. Mars isn’t what you might call geologically active, but it does commonly suffer landslides and avalanches when the frozen carbon dioxide ice under the surface sublimates (turns directly from a solid into a gas), which can dislodge material. If that happens at the top of a hill or cliff, material can cascade down dramatically. I strongly suspect that’s what we’re seeing in this video.