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Photographing the Moving Rocks at Racetrack Playa

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(Note: Originally posted in January, 2008.)

Earlier this week I posted an older photo from Racetrack Playa at Flickr and got a lot of comments and a few questions. In response, I said that I would post something here about this location – so here goes…

The Racetrack Playa is in Death Valley National Park in south-eastern California. The Playa is the site Death Valley NP’s famous moving rocks (a.k.a. “sliding rocks”) phenomenon. Rocks, some of which are television-sized, have left tracks behind them as they have traveled across the surface of the playa. (See a post from earlier today for one photograph – there are more in the Death Valley section of my Gallery.)

No one has actually seen the rocks move, but there has been a lot of speculation about the process by which the rocks manage to travel across the playa. I’m no expert on this, but here’s some of what I’ve heard. First of all, while you are free to have a different opinion, I’m not convinced that aliens did it. (Though it would be a heck of a good joke on us.;-)

One theory involved a combination of wind and water. While you might wonder how water could play a role in a dry place like Death Valley, it most certainly can. In fact a playa is a feature formed when water washes sediment down from surrounding hills into a lower basin. The water spreads onto the playa and drops its load of sediment. When the water dries it leaves behind an extraordinarily flat surface. The thought was that rocks sitting on a very slippery surface of the playa might be moved by strong winds. Observations tended to make this scenario unlikely. For example, it was calculated that the winds necessary to move the largest rocks would have to be several hundred miles per hour. It gets windy there, but not that windy.

A refinement of the theory adds ice to the mix. Imagine a thin layer of water on the playa with the slippery surface underneath. Now freeze a thin layer of ice on the top of the underlying water in this shallow “lake.” (And, yes, it very definitely gets cold enough there to freeze water.) Now the winds would not have to work directly on the rocks themselves, but could instead act on the whole frozen surface, much as they act on the arctic ice pack. As the ice moved, the rocks embedded in the ice would be dragged along. This seems to make sense given the observation that groups of rocks often follow parallel paths across the playa surface.

The rocks seem to come from a low rocky hill at the south end of the playa. While they can be found in many other areas of the playa, the greatest concentration is near this formation.

Access to the Racetrack Playa is typically by way of an awful 27 mile gravel road that starts near Ubehebe Crater. (I’m no expert on desert travel or on these roads, so consult the Park Service for current and more reliable information if you go.) The road has been badly washboarded every time I’ve been on it – some people are so distressed by the conditions on the road that they turn around after a few miles of driving. For most drivers this makes for very slow going and it can take up to about two hours to get out to the playa. I met one driver of a very large truck who was convinced that “once you get above 30 mph the road smooths out.” I don’t recommend that approach. Slow and careful is probably a lot safer, especially for those without extensive experience driving roads like these. I know that I sit back and take it slow.

The last time I checked the Park Service recommended a “high clearance vehicle” for this road, and I concur. I have seen some vehicles without such clearance and it seemed to be pretty rough going, not to mention that you increase the risk that the undercarriage will be damaged by rocks. (If it has rained or snowed, all bets are off. Best to stay away. You certainly aren’t going to walk on the playa when it is wet anyway, are you!?)

Soon after you pass Teakettle Junction you will catch your first view of the playa ahead and/or to the left. You still have a ways to drive before you arrive at the playa and drive along the right side. You’ll want to keep going if you plan to see the best rocks, though it is worth stopping at the Grandstand, a large rock formation in the playa not far from where it starts. I’ve had good luck photographing this feature during the late afternoon.

Continue on to pull-outs near the far end of the playa for closest access to the rocky hill and the largest number of moving rocks. You’ll need to leave your car and walk a good distance out onto the playa. (Don’t even think about walking on the playa unless it is completely dry. Foolish and inconsiderate visitors have done so, and their footprints mar the scene for years afterwards.) Before long you’ll start to see the rocks. One plan is to head for the low hill where the rocks originate and then explore outwards from there.

There is a small “camping area” a short distance beyond the end of the playa. It is very primitive, consisting of little more than a couple of wide spots in the road and one dilapidated outhouse. There is no water whatsoever. I have camped there and it is very quiet and peaceful. I’ve also see people sleep in their cars back at the turnouts right at the playa.

My ideal trip works something like this: Go during the cool season. Almost no one would want to try to visit this place in the summer. Most visit in late fall, winter, or very early spring. My visits have all been during the first week of April. Drive out to the playa in the afternoon, arriving a few hours before sunset. If you have time, stop to photograph the Grandstand in the afternoon light. Then head on down to the south end of the playa and figure out where you’ll sleep that night.

By the time the light starts to become interesting you’ll want to be out on the playa, perhaps with a few shots already scoped out. Shoot like crazy for the next few hours as the sun drops and finally sets, continuing on after sunset as long as the light is interesting. Head back to your car and grab some dinner. (The last time I visited I met some fellow photographers and we had a great time sharing food and drink.) If there is a full moon (or maybe even if there isn’t) head back out to do some night photography. This is a wonderful place to photograph star trails, and there are a ton of interesting opportunities on full moon nights once the moon finally makes it over the ridge located to the east. Finally, completely exhausted, head back to your camp for the night.

Rise early the next morning – well before sunrise. You want to already be out on the playa before the interesting light starts. The morning lighting is interesting and somewhat challenging. All I’ll say is that there are mountains to the east that block the first light, yet the very earliest light will illuminate some interesting subjects.

Soon, most of the playa is in full sun. I generally shoot a bit more, but by this time I’m running out of gas – and getting hungry for some real food. I head back to the car, say goodbye to the playa and start the long drive back to the paved road that begins near Ubehebe Crater. (Don’t pass up on photographic opportunities as you drive this road though.)

Finally, a few random thoughts – some in response to questions I’ve received.

  • Someone asked how often the rocks move? I’m not sure but not often – the interval must be measured in years.
  • Someone else asked how they keep visitors from “tracking it up” when it is wet? Good question, and an important one to mention. There are footprints on the playa left by inconsiderate visitors who wandered about when the playa was muddy. Their footprints remain for years. If you visit when the surface is wet please do not leave tracks on the playa, even if that means coming back a different time. Fortunately, the road is so long and so bad and there are no services out there – all of which drastically limit the number of visitors. I’ve seen perhaps as many as 20 people out there at once, but on one other visit there were only two of us.
  • Another photographer asked about the effect of the eastern ridge on sunrise photography. I touched on that above, but there is indeed a very tall ridge to the east that keeps the area with the concentration of rocks in the shadows until later in the morning.
  • And what about the ridge to the west at sunset? There is also a large ridge to the west of the main part of the playa, and the road past the playa runs along its lower east edge. This feature casts a shadow on the northern portion of the playa well before actual sunset. My advice it to photograph there a bit earlier – I’ve had good luck photographing “The Grandstand” in the late afternoon. The sun hits the southern portion of the playa later in the evening since the valley opens to the west from there.
Photographs: Death Valley, Photographs: Desert, Photographs: Nature, Photographs: Southern California

Crossing Tracks, Racetrack Playa

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Crossed Tracks, Racetrack Playa

Crossed Tracks, Racetrack Playa. Death Valley National Park, California. April 2, 2007. © Copyright 2007 G Dan Mitchell – all rights reserved.

The tracks of the famous “moving rocks” of the Racetrack Playa cross in evening light.

This was an absolutely beautiful evening on the playa, with wonderful light and interesting clouds. I was impressed by these long and straight moving rock trails that crossed and were heading in nearly opposite directions.

There is at least one believable theory about how the rocks moved. (No, not the one involving alien landings… ) It goes sort of like this: A playa like this one is formed by, believe it or not, flooding. During occasional wet seasons, the water washes down from the surrounding hills and fills the playa with silt and few inches of water. The original theory suggested that this was enough – that strong winds would be enough to move the rocks across the slick surface of the playa. (The rocks seem to come from a hill at the sound end of the playa.)

There is a problem with this notion. While the Racetrack is a very windy place, and the winds might be strong enough to move small rocks, someone calculated that in order to move the largest rocks the winds would have to be in the range of several hundred mph! The playa is windy, but no that windy!

Then someone realized that, counterintuitive though it may be, it can get cold enough on the playa to freeze the surface of water collected there. If the rocks were to become locked in the surface ice, the winds could act on the area of the ice surface much as they do on arctic ice packs. As the ice moves it might drag the rocks along, and if sections of the playa were frozen or if the ice broke up groups of rocks might be moved in the same manner. A further “refinement” of the theory suggests that if the surface froze as the water level was rising that rocks locked in the ice might even be slightly lifted, making it easier for them to move.

This seems reasonable given some of the visible evidence. In places groups of several rocks that are somewhat close together have left parallel curving tracks – the explanation is that they were locked together in a section of the ice that moved them in the same way. It even is consistent with the appearance of strange phenomenon such as these rock tracks that cross at right angles – they would have been moved at different times and under different wind conditions.

I have not read any theories about how often the rocks move. When I first heard about the place many years ago, I think I almost imagined a magical place where rocks were sailing about on the flat surface. Then I visited and I began to imagine that the rocks might only move in wet years – perhaps every decade or so. But with more visits and more thought, it began to seem to me (in my unscientific musings) that the conjunction of conditions required to move the rocks (flooding, freezing, plus high winds) might actually occur very rarely. I now make the assumption that the actual movement of the rocks may be a very rare thing, indeed.

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