(time-lapse photography) Source
The Sliding Rocks of Death Valley
(Racetrack Playa)
(time-lapse photography) Source
Explanation:
"Having experienced Death Valley wind events (most notably in July and December 1996) in which pebble-sized materials pelted the sides of the research vehicle, it is not difficult to imagine the local wind climate fostering even more dramatic effects. Given a near friction-free surface, as would be expected after a heavy rain or similar influx of water through runoff and subsurface flow, the Racetrack would most certainly be a dynamic place during strong wind events."
