wandering stones death valley

August 27, 2014

Mystery of Death Valley's "Wandering Stones" Explained

Scientists spot ice shoving rocks on Racetrack Playa in California, resolving a longstanding geological enigma

By Alexandra Witze & Nature magazine

Ending a half-century of geological speculation, scientists have finally seen the process that causes rocks to move atop Racetrack Playa, a desert lake bed in the mountains above Death Valley, California. Researchers watched a pond freeze atop the playa, then break apart into sheets of ice that — blown by wind — shoved rocks across the lake bed.

Until now, no one has been able to explain why hundreds of rocks scoot unseen across the playa surface, creating trails behind them like children dragging sticks through the mud.

“It’s a delight to be involved in sorting out this kind of public mystery,” says Richard Norris, an oceanographer at the Scripps Institution of Oceanography in La Jolla, California, who led the research with his cousin James Norris, an engineer at Interwoof in Santa Barbara, California. The work was published on August 27 in  PLoS ONE .

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing . By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

Geologists previously speculated that some combination of wind, rain and ice would have a role. But few expected that the answer would involve ice as thin as windowpanes, pushed by light breezes rather than strong gales.

Visitors to Death Valley have to go out of their way to visit Racetrack Playa, which sits 1,130 meters above sea level and is a bumpy three-hour drive from the nearest town. The researchers began studying the region in 2011, setting up a weather station and time-lapse cameras and dropping off rocks loaded with Global Positioning System (GPS) trackers. The rocks were designed to start recording their position and speed as soon as something made them move.

What was not clear was how long the Norrises would have to wait. Ralph Lorenz, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, has been studying the playa since 2007 as an analogy to lake beds on other planets. He had little faith that the GPS-equipped rocks would move in a time frame that anyone would capture. “I thought it was going to be the most boring experiment in the history of science,” he says.

But when the researchers travelled to the playa in December 2013 to check instruments and change batteries, they found a huge ice-encrusted pond covering about one-third of the 4.5-kilometer-long playa. After several days of camping, they decided to sit above the southern end of the playa on the morning of December 20. “It was a beautiful sunny day, and there began to be rippled melt pools in front of us,” Richard Norris says. “At 11:37 a.m., very abruptly, there was a pop-pop-crackle all over the place in front of us — and I said to my cousin, ‘This is it.’ ”

They watched as the ice began moving past the rocks, mostly breaking apart but also shoving them gently. The rocks began to inch along, but their pace was too slow to spot by eye. “A baby can get going a lot faster than your average rock,” Richard Norris says.

But when the ice melted away that afternoon, they saw freshly formed trails left behind by more than 60 moving rocks. And on January 9, James Norris returned to the playa with Lorenz and was able to record video of the roving rocks. “This is transformative,” says Lorenz. “It’s not just an anecdotal report, but we have before and after pictures, and meteorological information simultaneous with the event.” By the end of the winter, the farthest-moving rock had travelled 224 meters.

Racetrack Playa rocks move rarely — “maybe a few minutes out of a million,” Lorenz says. And the two events the scientists saw, with thin ice panes shoving the stones across a wet playa, do not necessarily explain every instance of rocks moving there. “But this breaks the back of the problem scientifically,” Lorenz says. “It is ice shove.”

Solving the Racetrack Playa mystery is not exactly a major scientific breakthrough, Lorenz says, but the work does show the rare combination of conditions that allow rocks to move seemingly on their own. And ice shove can have notable effects — in 1952, it uprooted enough telephone poles at a lake in Nevada to break a transcontinental telephone line.

One person who is happy to see the latest results is Dwight Carey. As a university student in the 1970s, he helped with an experiment in which two rocks were placed in a corral on the playa. Over the course of a winter, one stone moved out of the corral, unobserved, and the other did not. 

The new explanation “makes sense to me”, says Carey, who is now an environmental regulatory consultant in Brea, California. “Eventually you’re going to get enough force on the pile of ice behind the rocks to be able to move them.”

This article is reproduced with permission and was first published on August 27, 2014.

• Skip to global NPS navigation
• Skip to the main content
• Skip to the footer section

Exiting nps.gov

Death valley's moving rocks.

Photo by Jeffery Aiello

Racetrack Playa is home to one of Death Valley's most enduring mysteries. Littered across the flat surface of this dry lake, also called a "playa," are hundreds of rocks that seem to have been dragged across the ground. Sometimes these rocks—some weighing as much as 320 kilograms (700 pounds)—leave synchronized trails that can stretch for hundreds of meters. The rocks may sit for years without moving.

What causes these rocks to move? Researchers just recently found out. Remote observations from 2011 to 2013 showed it's a rare combination of water, ice, and wind.

Discover the details about the moving rocks of Death Valley , including a first-hand account from the researchers who may have solved this mystery.

A note about seeing the moving rocks: The surface of the Racetrack Playa is very fragile. Driving on it or anywhere off established roads is strictly prohibited. Do not move or remove any of the rocks and avoid walking in muddy areas when the playa is wet. A more easily accessible location to observe the tracks of sliding stones is the Bonnie Claire Playa east of Scotty's Castle. The south shore of the playa runs right along the north side of Highway 72. There is abundant evidence of sliding stones at this playa, which is believed to experience the same rock-moving conditions as the Racetrack. The area is administered by the Bureau of Land Management.

You Might Also Like

• death valley national park
• natural phenomena
• geoheritage sites

Death Valley National Park

Last updated: March 22, 2018

How Do Death Valley’s ‘Sailing Stones’ Move Themselves Across the Desert?

These mysterious rocks have puzzled scientists for decades—until one geologist found the answer on his kitchen table

Joseph Stromberg

Start at the Furnace Creek visitor center in Death Valley National Park. Drive 50 miles north on pavement, then head west for another 30 miles on bone-rattling gravel roads. During the drive—which will take you four hours if you make good time—you’ll pass sand dunes, a meteor crater, narrow canyons, solitary Joshua trees and virtually no evidence of human existence whatsoever.  But soon after cresting the Cottonwood Mountains, you’ll come upon a landscape so out of place even in this geologically bizarre park that it almost seems artificial. 

Racetrack Playa is a dried-up lakebed, ringed by mountains, about 3 miles long and flat as a tabletop. During summer, the cracked floor looks prehistoric under the desert sun; during winter, it’s intermittently covered by sheets of ice and dustings of snow. But the dozens of stones scattered across the playa floor are the most puzzling part of the view. Ranging from the size of a computer mouse to a microwave, each one is followed by a track etched into the dirt, like the contrail behind an airplane. Some tracks are straight and just a few feet long, while others stretch the length of a football field and curve gracefully or jut off at sharp angles.

Staring at these " sailing stones ," you’re torn between a pair of certainties that are simply not compatible: (1) these rocks appear to have moved, propelled by their own volition, across the flat playa floor, and yet (2) rocks don’t just move themselves.

“It’s very quiet out there, and it’s very open, and you tend to have the playa to yourself,” says Alan Van Valkenburg, a park ranger who has worked at Death Valley for nearly 20 years. “And the longer you stay out there, it just takes on this incredible sense of mystery.” The mystery is rooted in an extraordinary fact: No one has ever actually seen the rocks move.

Explanations for the stones’ movement have tended towards the absurd (magnetism, aliens and mysterious energy fields, for example). Some present-day visitors apparently agree—Van Valkenburg notes that stone theft is a growing problem, perhaps because of perceived special properties. “I don't know whether people think they're ‘magic rocks,’” he says. “But of course, as soon as you remove them from the playa, all ‘magic’ is lost.”

But if they’re not magic, what really does cause the stones to sail? In 1948, two USGS geologists named Jim McAllister and Allen Agnew set out to answer the question. They proposed that dust devils caused the strange movement, perhaps in combination with the playa’s intermittent flooding. In 1952, another geologist tested this hypothesis as directly as he knew how: He soaked a stretch of the playa and used a plane’s propeller to create powerful winds. Results were inconclusive.

In the following decades, theories drifted towards ice, which can occasionally form on the playa during the winter. During the early 1970s, a pair of geologists—Robert Sharp of Cal Tech and Dwight Carey of UCLA—attempted to settle once and for all whether ice or wind was responsible. The team visited the Racetrack twice a year and meticulously tracked the movements of 30 stones, giving them names (Karen, the largest boulder, was 700 pounds). They planted wooden stakes around the stones, surmising that if ice sheets were responsible, the ice would be frozen to the stakes, thereby immobilizing the stones. But some stones still escaped—and despite frequent visits, the pair never saw one move.

Still, ice remained the primary hypothesis for decades. John Reid, a Hampshire College professor, took student groups to the playa annually from 1987 to 1994 to study the stones. Because of the many parallel tracks, he came away convinced that they were locked together in large ice sheets that were blown by strong winds.

But Paula Messina , a geologist at San Jose State, used GPS to create a digital map of the tracks and found that most were, in fact, not parallel. Furthermore, wind-based models were thrown into doubt when researchers attempted to calculate the wind speeds necessary to move the ice sheets. The lowest figures were hundreds of miles per hour.

Enter Ralph Lorenz , a planetary scientist at Johns Hopkins University. In 2006, as part of a project with NASA, Lorenz was setting up a network of miniaturized weather stations in Death Valley. The weather is harsh enough there to serve an analogue for weather conditions on Mars. But then he discovered the sailing stones. “I was intrigued, as everyone is, and I had this instrumentation I was using in desert locations during the summer,” he says. “We realized we could use it during the winter and try to understand what the conditions really are at the playa.”

As the research team studied weather patterns on the Racetrack, they also looked for rocks that seemed to move on their own in other environments. Scanning the scientific literature, Lorenz learned that the buoyancy of ice helped float boulders onto arctic tidal beaches, creating barricades along the shore. The scientists began putting this idea together with what they saw on the Racetrack. “We saw one instance where there was a rock trail and it looked like it hit another rock and bounced, but the trail didn't go all the way up to the other rock, like it was repelled somehow,” says Lorenz. “We thought if there was a collar of ice around the rock, then it might be easy to imagine why it might bounce.”

Eventually, Lorenz employed a tried-and-true method for testing his nascent idea: the kitchen-table experiment. “I took a small rock, and put it in a piece of Tupperware, and filled it with water so there was an inch of water with a bit of the rock sticking out,” he says. “I put it in the freezer, and that then gave me a slab of ice with a rock sticking out of it.” He flipped the rock-ice hybrid upside down and floated it in a tray of water with sand on the bottom. By merely blowing gently on the ice, he realized, he could send the embedded rock gliding across the tray, scraping a trail in the sand as it moved. After decades of theoretical calculations by countless scientists, the answer seemed to be sitting on his tabletop.

Lorenz and his team presented their new model in a 2011 paper . “Basically, a slab of ice forms around a rock, and the liquid level changes so that the rock gets floated out of the mud,” he explains. “It’s a small floating ice sheet which happens to have a keel facing down that can dig a trail in the soft mud.” Calculations show that, in this scenario, the ice causes virtually no friction on the water, so the stones are able to glide with just a slight breeze. The team argues that their model accounts for the movement far better than any other, since it doesn’t require massive wind speeds or enormous ice sheets.

Still, says Ranger Van Valkenburg, most visitors to the Racetrack seem to resist this concrete explanation for such a peculiar phenomenon. “People always ask, ‘what do you think causes them to move?’ But if you try to explain, they don't always want to hear the answers,” he says. “People like a mystery—they like an unanswered question.”

In a way, though, Lorenz’ physical explanation really need not diminish the feeling of awe the sailing stones bring about—it can heighten it. You can get a sense of it by sitting at the playa and imagining the perpetual sailing of the stones over time, stretching into millennia. As human societies rise and fall, and as cities are constructed and then left to disintegrate, the stones will glide gradually around their playa, turning back and forth. Frozen in ice and nudged by the slightest of breezes, they will endlessly carve mysterious, zigzagging paths into the hard flat ground.

Get the latest Travel & Culture stories in your inbox.

Joseph Stromberg | | READ MORE

Joseph Stromberg was previously a digital reporter for Smithsonian .

Subscribe or renew today

Every print subscription comes with full digital access

Science News

Death valley’s sailing stones caught on the move.

Rock raceway controlled by ice and wind

ROCK SLIDE  Stones such as this one inscribe long trails as they slide across Death Valley. Scientists have found that ice and wind play a role in the rocks’ mysterious movements.

Thomas Hawk/Flickr (CC BY-NC 2.0)

Share this:

By Thomas Sumner

September 4, 2014 at 4:34 pm

For nearly a century Death Valley’s dancing rocks have amazed visitors and stumped scientists. Despite etching trails longer than football fields into the dried mud, no one had ever seen the stones move.

Last winter researchers employed GPS trackers and time-lapse photography to monitor dozens of rocks ranging from petite pebbles to hefty boulders. On December 20, they caught more than 60 stones sliding in unison at slothlike speeds of 2 to 5 meters per minute. The team describes  the event August 27 in PLOS ONE .

Numerous explanations have been proposed for the mass movements over the years, ranging from earthquakes to aliens. Tagging the rocks revealed that ice and wind power the locomotion. During some winters, rainwater pools in the normally bone-dry lakebed and freezes into thin rafts of floating ice. As the wind blows against these rafts, the ice shoves against the rocks, forcing them to grind along the mud and leave behind the telltale tracks.

Watch  The Racetrack Playa’s Sliding Rocks   for a detailed explanation of the phenomenon.

More Stories from Science News on Earth

Warm water is sneaking underneath the Thwaites Glacier — and rapidly melting it

‘The High Seas’ tells of the many ways humans are laying claim to the ocean

A weaker magnetic field may have paved the way for marine life to go big

A hidden danger lurks beneath Yellowstone

As the Arctic tundra warms, soil microbes likely will ramp up CO 2 production

A new approach to fighting wildfires combines local knowledge and AI

A ruinous hailstorm in Spain may have been supercharged by warming seas

Ximena Velez-Liendo is saving Andean bears with honey

Subscribers, enter your e-mail address for full access to the Science News archives and digital editions.

Not a subscriber? Become one now .

• Share full article

Advertisement

Supported by

An Icy Answer to the Mystery of the Moving Death Valley Stones

By Henry Fountain

• Sept. 1, 2014

Researchers have solved a longstanding mystery that has befuddled scientists and tourists alike: why rocks on a dry lake bed in Death Valley National Park in California occasionally move.

The explanation for the phenomenon at Racetrack Playa — named for the long trails that the rocks, some of which weigh hundreds of pounds, leave in the mud — is that the stones are pushed by wind-driven ice that forms and then breaks up under certain conditions.

“It’s a very rare phenomenon,” said Richard D. Norris , a paleobiologist at the Scripps Institution of Oceanography and lead author of a paper describing it in PLOS One. “A brief moment in time.”

Dr. Norris and James M. Norris, a cousin and co-author, actually saw the rocks moving in December when they went to check on the project. “It was complete dumb luck,” Dr. Norris said. “Almost every rock on the playa moved.”

Scientists have offered theories about these “sailing stones” since at least the 1940s. Many thought that wind or ice played a role, but not in the ways that the Norrises and colleagues uncovered. For their study, they embedded special global positioning system devices, designed by James Norris, in rocks of various sizes brought from outside the park, because the park service did not allow them to disturb the existing playa stones.

The playa, about three square miles and pancake flat, is usually dry, though rainwater runoff from the surrounding mountains occasionally fills part of it to a depth of a few inches. It’s when this shallow pond forms, and the nights are below freezing and the days are sunny and warm, that the rocks may move, the researchers said.

On those occasions, the cold night air leaves a sheet of ice barely an eighth of an inch thick. Then the warmth of the sun causes the sheet to break up.

“One moment, it’s quiet and still,” Dr. Norris said. “The next, it’s crackle, crackle, pop, pop, pop.”

As more ice melts, some of these lesser sheets have room to move. Driven by light breezes, the sheets push up against rocks and nudge them. The wind drives the water, too, which also helps push the ice against the rocks.

The movement is slow, no more than about 15 feet a minute. “The rocks are creeping along,” Dr. Norris said, “like a baby on its stomach.”

The researchers have not calculated the forces involved — that is grist for a future study, they said — but clearly, they are enough to move the rocks, aided by the reduced friction that comes from their sitting in the shallow water.

The movements are episodic — the conditions may be just right for a few minutes, and then the sun causes more ice to break and the movement stops. And once the water evaporates, it may be years before the rocks move again, even if the playa floods again, because the precise temperature and wind conditions may not occur.

“What you see 99 percent of the time you’re out there are these fossilized trails,” Dr. Norris said. “Everything has just stopped and gone into hibernation.”

The discovery also explains why many of the trails are parallel to one another. The researchers found that the moving ice sheets were sometimes so big that they would nudge rocks hundreds of feet apart, moving them in the same direction.

Based on existing theories, the cousins had thought that winds as high as 80 or 90 miles per hour might have moved the stones. So early in the two-year study, they discussed buying a sturdy all-season tent for their site visits.

They were surprised to see the rocks moving on a sunny day in a light breeze.

“We didn’t need the tent,” Dr. Norris said.

• Environment

Solved: Mystery of Moving Stones in Death Valley

S o-called sailing stones in California’s Death Valley National Park have perplexed tourists and scientists alike for their apparent ability to move on their own, leaving sometimes meter-long tracks in their wake.

But after years of speculation, researchers with patience , remote weather monitors, cameras, and stones that are fitted with GPS say they have discovered the force behind the phenomenon.

Wind (very strong winds) and ice (very thick ice) have long been considered as possible explanations for why the rocks, sometimes weighing hundreds of pounds, move. It’s actually a combination of a little of both, the team of researchers say in their study, published in the journal PLOS One this week .

Rainwater in what is known as the Racetrack Playa creates a shallow pond over the playa that, in cold winter temperatures, freezes over. When the ice begins to melt under the sun, it first breaks up into large panels thin enough that, with a nudge from even light winds, they shift — and push whatever rocks may lie in their path.

More Must-Reads from TIME

• How Selena Gomez Is Revolutionizing the Celebrity Beauty Business
• TIME100 Most Influential Companies 2024
• Javier Milei’s Radical Plan to Transform Argentina
• How Private Donors Shape Birth-Control Choices
• The Deadly Digital Frontiers at the Border
• What's the Best Measure of Fitness? 
• The 31 Most Anticipated Movies of Summer 2024
• Want Weekly Recs on What to Watch, Read, and More? Sign Up for Worth Your Time

Write to Noah Rayman at [email protected]

Death Valley’s Slithering Stones

PDF (black and white)

PDF (color)

For decades, Death Valley held a mystery that scientists could not solve.

Large rocks were slithering across the valley floor, traveling hundreds of meters, leaving long tracks behind them.

But no one had seen them do it or could figure out how it happened.

So, scientists fitted rocks with GPS trackers and set up remote cameras to try to capture the rocks in motion.

Because the movements could be separated by decades, they expected this to be “the most boring experiment ever.”

But just two years in, they got very lucky: they were in Death Valley one cold December to change the GPS batteries … and saw the rocks move in person.

And figured out the rare combination of conditions that made it happen.

The valley floor had to cover with water, from rain or melting snow. The night had to be cold enough to form a thin sheet of ice across its surface.

The next day had to be warm enough to break up the ice into large floating panels, up to 50 feet wide.

Then a light, steady wind was needed to gently push the ice islands across the water, slowly nudging the rocks along with them, across the slippery mud bottom.

By midday, the ice and water had evaporated, and the scientists saw long trails behind the now displaced rocks. Their cameras and GPS trackers captured it all.

Synopsis: California’s Mojave Desert is the home of Death Valley, the lowest, hottest and driest place in the United States. In Death Valley’s Racetrack Playa, boulders move inexplicably along winding paths, and no one had ever seen them move until curious scientists with GPS trackers solved the enigma.

• This is largely because it is the lowest place in the United States, sitting at -282 ft (-86 m) below sea level.

• Death Valley is enclosed by the Amargosa and Panamint Ranges to its east and west and the Grapevine and Owlshead Mountains to its north and south, respectively.
• Topographic relief is notable, with elevations in the Panamint Range exceeding 11,000 ft (3,353 m).
• Death Valley is perpetually dry because the rain shadows of four mountain ranges between Death Valley and the Pacific cause orographic lifting of west-flowing Pacific moisture that rains out along the western slopes of those ranges, leaving little to no moisture in the air reaching the graben. In some years no precipitation occurs.
• In summer, the deep valley traps superheated air between the surrounding mountain ranges that is reheated as the sun bakes the dark desert floor.
• Conversely, in winter, the valley traps cold air and temperatures as low as 15°F (-9°C) have been recorded during severe winter storms.

• Racetrack Playa is a flat-lying dried-out lakebed that is 2.8 mi (4.5 km) long by 1.25 miles (2 km) wide, just west of the Panamint Range.
• People have noted the changing locations of these rocks and their trails since the 1940’s, but no one had ever caught them in the act of moving.
• Most of the moving rocks are 20 pounds (9 kg) or larger and leave wide tracks in the mud.
• Scientists never found footprints around recently shifted rocks, ruling out hoaxes, but theories abounded, including relocation by hurricane-force winds or dust devils, plowing by thick ice sheets and sliding on slippery algal films.
• They embedded GPS trackers and time-lapse cameras in 15 stones that they carefully placed near rocks that had previously moved.
• They returned to the park to replace batteries in the trackers every few months, but nothing happened for two years.
• Colleagues called it “the world’s most boring experiment.”
• The scientists recognized that they might get usable data but were unlikely to actually observe the phenomenon, but they soldiered on.

• As night approached, temperatures dropped below freezing and ice began crystallizing across the playa.
• In the morning as the sun started shining, light winds began blowing at around 10 mph (5 m/s).
• As the ice began to crack, popping noises reverberated across the surface.
• Then, very thin (1/4 in [3–5 mm]) sheets of ice as much as 50 ft (15 m) across began to hydroplane slowly over the meltwater, pushing the slithering rocks along, leaving paths bulldozed in the muddy lakebed.
• The GPS trackers documented the rock movements, recording speeds of up to several feet per minute.
• Some rocks moved for as long as 16 minutes and as far as 200 ft (60 m), and some moved multiple times during the five floating-ice events that occurred over the next 10 weeks before the playa finally dried out again.
• Researchers determined that the last event like this had probably occurred unwitnessed in 2006, so the scientists were overjoyed to have been able to witness the rare event.
• The icy secret of Death Valley’s slithering stones was solved, introducing us to the amazing power of floating ice.

July 22, 2013

The Mystery of Death Valley's "Sailing Stones" Solved (...again)

By David Bressan

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American

"I love to sail forbidden seas, ... "

Herman Melville in " Moby Dick " (1851)

Strange tracks cover a muddy plain, located in a remote part of Death Valley National Park , named appropriately Racetrack-Playa . Most of these tracks end behind large boulders of dolostone or syenite, some however start and end without an apparent object nearby. In the first case, it seems reasonable to assume that the rocks moving along the ground formed the furrows - however nobody ever observed the actual process of formation.

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing . By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

The sailing rocks of Death Valley were studied since 1948, when geologists Jim McAllister and Allen Agnew mapped the area and noted the tracks. In March 1952 geologist Thomas Clement tried to observe the rocks moving, but a heavy thunderstorm forced him into his tent. Only the next morning he noted fresh formed tracks on the ground and a thin layer of water covering the ground. As most of the tracks coincide with the overall wind direction (southwest to northeast), it was assumed that the wind pushed the rocks over the wet and slippery mud. However this hypothesis could explain only a part of the moving rocks, especially the smaller ones. Curiously there is no correlation between the size of the rock and length of the track, even if it seems that larger boulders seem to travel less than smaller ones.

In the following years the strangest ideas tried to explain the mystery of Racetrack-Playa: extraterrestrials, geologists or animals pushing the stones, a hoax to fool tourists, earthquakes, magnetic or gravitational anomalies and unknown wind and water currents.

Geographer George Stanley Druhot (1914-1983) assumed a dominant role of ice, not only as slippery surface, but also as a sort of sail, when ice forms plates around the boulders and increases the surface on which the wind can act.

In 2010 a research team from various institutions ( NASA , Slippery Rock University (!)- Pennsylvania, University of Wyoming ) reanalyzed the geological and meteorological conditions at Racetrack-Playa, finding evidence to support Stanley´s idea. Geologist Paula Messina showed that the ground is covered by argillaceous sediments and bacterial mats, forming under wet conditions a very slippery surface. The climatic data showed also that ice can in fact form during wintertime in Death Valley, when also most tracks on Racetrack-Playa are formed. The ice hypothesis ( and similar models ) explains also the tracks without apparent object nearby, as the chunk of ice melted after the formation of the track, and the deepening of some furrows behind the respective boulder, as the plate of ice surrounding the boulder melts, the rock tends to sink deeper into the mud.

Most researchers agree that a simplistic - one factor assuming - model fails to explain all the sailing rocks. It´s probably the odd combination of mud and bacteria, forming a slippery ground, the topography, forcing the wind into one prevalent direction, the sizes of the boulders, the particular temperature changes experienced in Death Valley and the occasional formation of ice, that like a ghostly hand moves the rocks around the desert.

Bibliography:

MILLER, M.B. (2005): Geological landscapes of the Death Valley region. Earth-Science Review 73:17-30

Awesome, you're subscribed!

Thanks for subscribing! Look out for your first newsletter in your inbox soon!

The best things in life are free.

Sign up for our email to enjoy your city without spending a thing (as well as some options when you’re feeling flush).

Déjà vu! We already have this email. Try another?

By entering your email address you agree to our Terms of Use and Privacy Policy and consent to receive emails from Time Out about news, events, offers and partner promotions.

• Things to Do
• Food & Drink
• Time Out Market
• Coca-Cola Foodmarks
• Los Angeles

Get us in your inbox

🙌 Awesome, you're subscribed!

Did you know that Death Valley is full of mysterious moving stones?

The ‘sailing stones’ of Racetrack Playa were a mystery to scientists for more than a century

Picture this. All over a flat, dried-up lake in famously desolate Death Valley are hundreds of huge rocks, spread randomly. Behind each of them lies an impossibly smooth trail, as if the rocks have been pushed along the ground. But they’ve done that without any animals or humans touching them – and, to the naked eye at least, they don’t appear to be moving at all.

The rocks are called ‘sailing stones’, and they’re best found on Racetrack Playa, a dry lake in  California . So, what actually causes them to drift across the valley?

For decades people blamed high winds, magnetic fields and even aliens for the rocks’ tracks. Even geologists were completely mystified, only able to make wild guesses about how the hundreds of stones – some weighing as much as 320kg – moved. But by the mid-2010s, scientists reckoned they’d figured it out, once and for all.

Essentially, the rocks require a very, very rare combination of conditions to move. First, there has to be enough rainfall for the plain to fill with a few inches of water. It then has to get cold enough overnight to form floating ice, which lifts the rocks slightly. The next day has to be particularly sunny, thereby melting the ice in huge sheets. The wind then helps the melting ice slide the heavy rocks along the plain.

When all the ice is gone, voilà!  You’re left with the rocks having both moved and left an almost artificially smooth trail behind them. It is technically possible for the human eye to spot the rocks moving during these conditions, but it’s actually pretty difficult. After all, when a landscape is as barren as Death Valley, and there are no reference points for lots of rocks all moving at the same pace, how do you tell? If you want to read up on a recent study about the phenomenon, click  here .

In any case, they make for a fascinating visit – if you’re up for the trip, that is. Racetrack Playa is pretty remote. It’s about three and a half hours away from the nearest proper settlement, Furnace Creek, and the journey is only possible by 4x4.

But most important is that if you do make the trip, be a considerate tourist. Recent years have seen the playa and its sailing stones damaged and vandalized. Walking or driving on the wet plain can impede the rocks’ movement, and inscribing your initials on (or even stealing) the rocks is, obviously, a dumbass move. Some people, eh?

While you’re here, did you know that  this fire that has been raging in the Asian desert for 50 years ?

And have you heard the one about the  Dutch town with precisely zero roads ?

• Ed Cunningham News Editor, Time Out UK and Time Out London

Share the story

An email you’ll actually love

Discover Time Out original video

• Press office
• Investor relations
• Work for Time Out
• Editorial guidelines
• Privacy notice
• Do not sell my information
• Cookie policy
• Accessibility statement
• Terms of use
• Copyright agent
• Modern slavery statement
• Manage cookies
• Advertising

Time Out products

• Time Out Worldwide

Death Valley Mystery: What Makes Rocks Wander

A section of California's Death Valley is home to a strange phenomenon: Rocks that litter the landscape seem to move on their own, leaving long trails behind them in the cracked, bone-dry clay.

These wanderings have baffled scientists for more than five decades. Nobody has ever caught a glimpse of the stones actually moving, yet move they must, because the rocks' locations, and the trails they leave behind them, change over time.

A group of young scientists is taking a crack at solving the puzzle of this odd desert area known as Racetrack Playa.

Most of the wandering stones are about the size of a one-liter soda bottle and far heavier, according to Brian Jackson, a NASA scientist who has been studying the area for more than four years.

"You don't expect 20-pound (9-kilogram) rocks to go sliding across the ground very easily, but they seem to do that on occasion," Jackson said.

Jackson said crackpot theories abound to explain the stones' travels across the playa (a term for a dried-out lake bed ), which is about 3 miles (4.5 kilometers) long, almost a mile and a half (2 km) across, and preternaturally flat.

"I've definitely heard aliens, magnetic fields, frat boys from UNLV" — the University of Nevada, Las Vegas — "but nothing really plausible," Jackson said. "There's no way it could really be a hoax, because if someone were pushing them you'd see footprints."

Sign up for the Live Science daily newsletter now

Get the world’s most fascinating discoveries delivered straight to your inbox.

Earlier this summer, a group of interns from NASA's Lunar and Planetary Science Academy, a program run by the Goddard Space Flight Center in Maryland, headed west to study the phenomenon. In addition to collecting GPS measurements and myriad other data, the students retrieved instruments that had been buried in the ground three months earlier. The sturdy little instruments they dug up, called hygrochrons, are about the size of a quarter and measure humidity and temperature; they had been planted by NASA researcher Gunther Kletetschka.

The interns plan to publish a paper this year presenting their findings, which so far seem to back up a current theory that during the winter months, ice forms around the rocks, allowing them to slip across the frozen surface of the playa.

Jackson said the data the interns gathered during their expedition confirmed that the playa had been wet and cold enough over the winter to form ice. "So that's encouraging," he said. "That tells us that at least some of the conditions required to move these rocks were met. It's pretty clear these rocks are assisted by ice somehow." Some scientists think algae blooms may play a role, he added.

Besides looking to Racetrack Playa to help solve mysteries on our own planet , researchers are examining the area to better understand conditions on other worlds. Jackson is co-author of a recent study, led by Johns Hopkins University's Ralph Lorenz, comparing the meteorological conditions of the region to those near Ontario Lacus, a vast, liquid hydrocarbon lake on Saturn's moon Titan .

Jackson said the continuing mystery of the moving rocks doesn't bother him and that, in fact, perplexing problems are a boon to science.

"Science is really all about ignorance," Jackson said. "I think the most exciting science is done in places where you don't understand what's going on. Once you're not confused about something, it's time to move on to the next problem."

• The 7 Most Mysterious Archeological Finds on Earth
• 7 Ways the Earth Changes in the Blink of an Eye
• The Harshest Environments on Earth

This article was provided by OurAmazingPlanet , a sister site to LiveScience.

Cutting pollution from the shipping industry accidentally increased global warming, study suggests

The 165-year reign of oil is coming to an end. But will we ever be able to live without it?

Japan loses contact with Akatsuki, humanity's only active Venus probe

Most Popular

• 2 Things are finally looking up for the Voyager 1 interstellar spacecraft
• 3 Auroras could paint Earth's skies again in early June. Here are the key nights to watch for.
• 4 Scientists may have finally solved the problem of the universe’s 'missing' black holes
• 5 World's 1st carved horse: The 35,000-year-old ivory figurine from Vogelherd cave
• 2 Wreck of WWII 'Hit 'Em Harder' submarine, which sank with 79 crew on board, discovered in South China Sea
• 3 3,500-year-old rock art of wild sheep and double-humped camels revealed in Kazakhstan
• 4 Cutting pollution from the shipping industry accidentally increased global warming, study suggests
• 5 Elusive 'octopus squid' with world's largest biological lights attacks camera in striking new video

Pictures: What Drives Death Valley's Roving Rocks?

What causes stones to sail in the hottest place in North America? New evidence suggests the mysterious rocks "float" on winter ice.

Related Topics

You may also like.

A glass revolution is underway. Spoiler alert: it bends and bounces

This legendary gemstone is real—but was it actually cursed?

How to buy crystals that don’t harm people or the planet

A tsunami could wipe this Norwegian town off the map. Why isn’t everyone leaving?

Your guide to a rock-collecting adventure with kids

• Environment
• Paid Content
• Photography
• Perpetual Planet

History & Culture

• History & Culture
• History Magazine
• Mind, Body, Wonder
• Terms of Use
• Privacy Policy
• Your US State Privacy Rights
• Children's Online Privacy Policy
• Interest-Based Ads
• About Nielsen Measurement
• Do Not Sell or Share My Personal Information
• Nat Geo Home
• Attend a Live Event
• Book a Trip
• Inspire Your Kids
• Shop Nat Geo
• Visit the D.C. Museum
• Learn About Our Impact
• Support Our Mission
• Advertise With Us
• Customer Service
• Renew Subscription
• Manage Your Subscription
• Work at Nat Geo
• Sign Up for Our Newsletters
• Contribute to Protect the Planet

Copyright © 1996-2015 National Geographic Society Copyright © 2015-2024 National Geographic Partners, LLC. All rights reserved

Death Valley mystery: What makes rocks wander

A section of California's Death Valley is home to a strange phenomenon: Rocks that litter the landscape seem to move on their own, leaving long trails behind them in the cracked, bone-dry clay.

These wanderings have baffled scientists for more than five decades. Nobody has ever caught a glimpse of the stones actually moving, yet move they must, because the rocks' locations, and the trails they leave behind them, change over time.

A group of young scientists is taking a crack at solving the puzzle of this odd desert area known as Racetrack Playa.

Most of the wandering stones are about the size of a one-liter soda bottle and far heavier, according to Brian Jackson, a NASA scientist who has been studying the area for more than four years.

"You don't expect 20-pound (9-kilogram) rocks to go sliding across the ground very easily, but they seem to do that on occasion," Jackson said.

Jackson said crackpot theories abound to explain the stones' travels across the playa (a term for a dried-out lake bed ), which is about 3 miles (4.5 kilometers) long, almost a mile and a half (2 km) across, and preternaturally flat.

"I've definitely heard aliens, magnetic fields, frat boys from UNLV" — the University of Nevada, Las Vegas — "but nothing really plausible," Jackson said. "There's no way it could really be a hoax, because if someone were pushing them you'd see footprints."

Earlier this summer, a group of interns from NASA's Lunar and Planetary Science Academy, a program run by the Goddard Space Flight Center in Maryland, headed west to study the phenomenon. In addition to collecting GPS measurements and myriad other data, the students retrieved instruments that had been buried in the ground three months earlier. The sturdy little instruments they dug up, called hygrochrons, are about the size of a quarter and measure humidity and temperature; they had been planted by NASA researcher Gunther Kletetschka.

The interns plan to publish a paper this year presenting their findings, which so far seem to back up a current theory that during the winter months, ice forms around the rocks, allowing them to slip across the frozen surface of the playa.

Jackson said the data the interns gathered during their expedition confirmed that the playa had been wet and cold enough over the winter to form ice. "So that's encouraging," he said. "That tells us that at least some of the conditions required to move these rocks were met. It's pretty clear these rocks are assisted by ice somehow." Some scientists think algae blooms may play a role, he added.

Besides looking to Racetrack Playa to help solve mysteries on our own planet , researchers are examining the area to better understand conditions on other worlds. Jackson is co-author of a recent study, led by Johns Hopkins University's Ralph Lorenz, comparing the meteorological conditions of the region to those near Ontario Lacus, a vast, liquid hydrocarbon lake on Saturn's moon Titan .

Jackson said the continuing mystery of the moving rocks doesn't bother him and that, in fact, perplexing problems are a boon to science.

"Science is really all about ignorance," Jackson said. "I think the most exciting science is done in places where you don't understand what's going on. Once you're not confused about something, it's time to move on to the next problem."

• The 7 Most Mysterious Archeological Finds on Earth
• 7 Ways the Earth Changes in the Blink of an Eye
• The Harshest Environments on Earth