Racetrack Playa

USA / California / Keeler /
 lake, rocks, mysterious, interesting place

The "Racetrack" playa is one of the most enigmatic geologic features in the world.
Rocks slide across the playa surface and leave tracks.The rocks have been called “playa scrapers” and the “sliding stones.” There has been a great deal of research done on these rocks over the years, but no one has ever seen them move. Five geology students even spent an entire winter in the area and every time the weather turned bad, they stopped by to see if anything happened. Nothing did. This phenomenon has been reported from other playas including the Bonnie Claire dry lake and Superior lake beds in California, one in Utah, and one in Tunisia. In no case has movement ever been witnessed. General assumption is that the playa must be wet (and therefore slick) and winds give the impetus. The role of ice (or lack thereof) has been, as it were, hotly debated.
Until someone actually observes the movement, no one can be sure.
Beside the sliding stones, there are other interesting geologic features in the valley. There is a large outcrop of granite sticking out of the playa at its north end. This outcrop, called the Grandstand, is a source for a few of the sliding stones. Bedrock protruding from a playa is quite unusual. So, too, is the nearness of the dolomite ridge at the southeast edge of the playa here where most of the sliding stone phenomenon occurs. The obvious conclusion is that mass wasting from these two sites initially supplies the stones that later slide across the playa. The dolomite rocks break into rather rectangular chunks which may facilitate their sliding under whatever conditions required.

In 2014 the stones were seen to move by patient scientists. A video was even posted on the internet. Pools of water froze overnight. When the sun came up and the ice layers starter to thaw and weaken Winds would push them along. Often the ice layers would shatter against the stones and at times remain firm and shove the stones along the wet playa. Rocks were seen to move considerable distances in a short time.
Nearby cities:
Coordinates:   36°40'51"N   117°33'31"W

Comments

  • The running theory for the rock movement is that when a storm comes through it turns the playa into a very slick mud, and that combined with strong winds allows the rocks to get blown across the surface.
  • Sometimes you can find gradually widening tracks which do not finish with a rock at all. I dug into one of such tracks at a softer side of the Playa and found a halfburied stick at the end of the track. Human intervention can not be excluded in some tracks.
  • Can you take a rock and sell it?
  • No, you can not take a rock. National park Service regulations forbid it or sticks picked up and used for walking or any other natural park stuff. Period. As for the sliding has anyone set a suitable rock on a wet, non NPS playa and tried moving it with a wind machine? That could rule out some of the theories?
This article was last modified 10 years ago