I have been posting photographs from my recent Death Valley trip here over the past week or so – and there are many more still to come. Many of the photographs were taken at the Racetrack Playa, the location of the famous “moving rocks.” Whenever I post photographs from the Racetrack, I get questions about this phenomenon. Rather than answering them individually, I’ve decided to post some information here.

Crossed Tracks, Racetrack Playa. Death Valley National Park, California. April 4, 2007. © Copyright G Dan Mitchell. (Sales)

The Racetrack is a playa, a very flat surface, typically in a desert area, created when silt is suspended in runoff and carried down from surrounding hills where it collects in the bottom of a valley that does not have an outlet stream. Such playas are, I hear, the flattest surfaces on the planet.

The main unusual feature of this playa is the existence of rocks that appear to have moved across the surface of the playa. While many of the rocks are fairly small, some are television sized, so the sight of a very large heavy rock that has obviously travelled across the playa and left a very long track – sometimes hundreds of feet long – in its wake is quite striking. The largest collection of the rocks is found at the south end of the playa near a rocky peak which is apparently the source of the rocks.

The Source. Death Valley National Park, California. April 3, 2007. © Copyright G Dan Mitchell. (Sales)

I’m no expert on the geology of the place, but here’s what I have heard about how the rocks may move. One theory was that during a wet winter the rocks could be blown across the wet and slippery surface of the playa. However, I believe that someone calculated how strong the winds would have to be to move the largest rocks and when they came up with a figure of 800 mph it seemed that the answer was going to be a bit more complicated. The Racetrack is, indeed, a very windy place… but not that windy!

Some groups of rocks have curved and turned in a way that makes it seem that they were moving in lockstep. More recent speculation is that that during a very cold, wet winter the surface of the shallow water that can flood the playa might freeze around the rocks but not freeze all the way down to the silt surface of the playa itself. The rocks would be locked into the frozen surface and it is possible to imagine winds strong enough to move the entire frozen surface, dragging the rocks along with the ice.

Or maybe aliens did it.

Curving Track, Racetrack Playa. Death Valley National Park, California. April 3, 2007. © Copyright G Dan Mitchell. (Sales)

The Racetrack Playa is is a fairly remote area of Death Valley National Park. It is a 50+ mile drive on a very rough gravel road that is badly washboarded in spots. The Park Service recommends that visitors be equipped for both the desert terrain and the road conditions – they suggest driving a high clearance all-wheel-drive vehicle. It takes me a bit more than two hours to drive the gravel section from Ubehebe Crater to the Racetrack.

I have seen quite a few people go to the trouble of traveling all the way to Death Valley National Park and then drive this very difficult road to the Playa just to see the rocks… in the middle of the day. Midday is not the most photogenic time in the desert, and the Racetrack is much more appealing – for viewing and for photography – in the late afternoon and at sunset, and again at sunrise and in the early morning. If you are going to put in the effort required to get to the Racetrack, I strongly recommend that you arrive in the mid-afternoon and stay overnight. It is OK to camp at Teakettle Junction, about six miles before the Racetrack, and there is a small camping area a few miles past the Playa. Some people simply sleep in their cars. There is no water and no other services there, so this is camping at its most primitive.

Dawn, Racetrack Playa. Death Valley National Park. April 3, 2007. © Copyright G Dan Mitchell. (Sales)

—–