The Racetrack Playa

The Racetrack Playa. Death Valley National Park. , In front of you is a dry lake bed - a playa - the flattest of all natural surfaces. , Fine mud and silt, eroded from the surrounding mountain, compose the playa. Water washes across the playa, suspending the sediments in a shallow, temporary lake. The particles then settle evenly over the lake bottom, maintaining a level surface as the water evaporates. , Resembling an island in a frozen lake, the Grandstand is an outcrop of bedrock surrounded by a sea of sediment. , This playa is called "The Racetrack" because of its famous moving rocks. Most of the rocks can be found at The Racetrack's southern end. , Please stay off the playa when it is wet; footprints last for years. , Moving Rocks , The rocks on this ancient lake bed move. , The moving rocks are something of a mystery. Scientists theorize that when this ancient lake bed - or playa - gets wet, it becomes so slippery that winds can move rocks weighing 100 pounds or more. Others suggest that winds move the rocks only when ice helps raft them along a temporary lake surface. , The moving rocks are about a half-mile walk from here. Please stay off the playa when it is wet; footprints last for years. Please do not remove the rocks; they become meaningless when moved out-of-place. , We may be uncertain how the rocks move, but we do know how far they travel. Their trails are clearly visible on the playa sarface.