Home > Science and Technology, Weekend Feature, Weird and Interesting > Sailing Stones: the weird, wandering desert rocks

Sailing Stones: the weird, wandering desert rocks

Sailing Stone in the desert

Where do you think you’re going, stone?

Check that out.

Crazy, right?

No footprints. No traces of something pushing it. It just looks like that rock crawled across the desert, turtle style.

It’s not even a round rock. Look how sharp those edges are!

So what’s the deal?

Well, that’s the question geologists and visitors to Death Valley National Park have been asking for years.

That there is a sailing stone, so named because – for reasons beyond explanation – it’s somehow managed to sail across a flat desert landscape without rolling on its own or being pushed by something else. It didn’t walk. It didn’t tumble. It just sailed, as you can see from the trail.

And that’s not the only stone to do it.

Zig Zag Sailing Stone in the desertDeath Valley Sailing StoneSailing Stones crossing paths in the desertMultiple Sailing Stones
The sailing stone phenomenon is unique to the Racetrack Playa, a dried up lake bed in Death Valley, where some 162 rocks weighing up to several hundred pounds have been found at the ends of long, snail-like trails through the desert.

Some of these trails are straight; others zigzag across the hardened mud. Oftentimes one stone’s path runs parallel to another’s; other times, they cross and weave around each other.

The tracks are created on the rare occasions when the ground is moist and covered in a thin layer of mud. That same layer of mud would pick up footprints from humans or animals doing the moving, but no such footprints have ever been discovered.

So how does it happen?

Geologists have been coming up with theories on the phenomenon for years.

One argument suggests that the playa is slightly slanted, and that the rocks are sliding ever so imperceptibly downhill.

That theory was discounted when it was determined that most of the stones were moving north – toward the higher end of the playa – and so could not be driven by gravity.

Other, more widely believed theories use wind, water, and ice to explain it. Deserts are huge, flat, and dry, so harsh winds often whip across the expanse. It’s the water and ice that are rare.

Because the lake bed of the playa is so dry, when it does rain or snow there is nowhere for the water to seep into the sun-baked earth. Instead, the water forms a thin layer across the top of the playa, and during the winter, that water freezes.

One theory is that the ice freezes around the sailing stones and then is buoyed up by water beneath. As the ice rises, so too do the stones, which then slide away across the water.

Picture that.

If you live somewhere with snow, have you ever seen your car drift away because it’s got snow in the tire treads?

Doesn’t happen.

The second wind/water/ice theory is a little more reasonable.

After the playa has been flooded by a rainstorm or a winter thaw, a thin layer of the hardened earth gets turned to mud. We’re talking nothing more than the top layer of dust on the surface. It’s no more than an inch, but it’s just enough to allow the wind to imperceptibly shove the rock and create the raised wake.

Geologists believe that the gale force winter winds that whip across the Racetrack Playa may be strong enough to ever so slightly move the rocks across the slick muddy surface. They only move a short distance each year, but it’s enough to explain the long raised tracks – and the changes in direction that would result from capricious winds.

There is no documented proof of the stones in motion. We have only the snail-like trails of the sailing stones on the Racetrack Playa to prove that they have indeed moved.

The video below claims to be proof, but it’s not quite that. Rather, it presents the water and ice theories and shows you how they work. It doesn’t show an actual stone moving, but it still gives a pretty good sense of how it all works.

Geologists track the stones, but they’re not allowed to plant cameras on them to monitor their progress. The guy in the video above must’ve found a way around Death Valley’s ban on visitors during rainy season, because he’s got some of the only footage of the winter Racetrack Playa. Even then, he doesn’t have footage of the rocks actually moving.

Despite some strong theories, the sailing stones of Death Valley will remain an unsolved mystery for as long as the national park forbids invasive technology.

My theory?

The stones are really old turtles.

Turtle crawling through sand with trail

Prove me wrong, geologists.

  1. April 6, 2013 at 8:10 am

    Crazy. Maybe they’re being ‘superconducted’ somehow…

  2. Anders
    July 25, 2013 at 6:38 am

    The rocks are alive! Or.. I believe the water ice theory. When the halve soaked rock freezes in during night it gets fixed in the ice layer. In the morning when the wind pickes up, the ice brakes into big pieces and start to move in the wind direction, dragging the stones with it. I bet the wind mostly blows north there?!

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