Death Valley’s Sailing Stones Only Move When Ice Forms, Scientists Finally Captured It on Camera

In a remote stretch of California inside Death Valley National Park, there is a dry lakebed called Racetrack Playa. At first glance, it looks empty. Cracked earth stretches toward distant mountains. But scattered across the flat surface are rocks, some weighing over 200 pounds. Long trails are etched behind them.

For decades, no one had actually seen these stones move.

Visitors would return to discover fresh tracks snaking across the playa for hundreds of feet. The boulders seemed to creep on their own. Hypotheses ranged from fierce desert winds to subtle earthquakes. Lacking concrete evidence, the enigma persisted.


That changed in 2013 and 2014, when researchers finally documented the stones in motion and published their findings in the peer-reviewed journal PLOS ONE.

Rain Briefly Floods the Playa

The process begins with rain, something rare in Death Valley.

During certain winter storms, rainfall or snowmelt from nearby mountains flows into Racetrack Playa. The normally dry lakebed turns into a shallow pond. The water is usually only a few centimeters deep, but it spreads evenly across the smooth clay.

The rocks sit partially submerged on this slick mud. While water alone doesn't move them, it lowers friction and prepares the stage for what comes next.

A Thin Sheet of Ice Forms Overnight

When nighttime temperatures drop below freezing, the shallow water freezes.

According to the 2014 study led by Richard Norris and his team, the ice that forms is surprisingly thin, typically just 3 to 6 millimeters thick. It is strong enough to cover the pond overnight, yet fragile enough to break apart the next day.

By morning, the playa transforms: a delicate, glass-like ice sheet covers the surface. In one of the hottest places in North America, this unexpected ice becomes the key ingredient.

Morning Sun Breaks the Ice Into Panels

As the sun rises, the ice begins to thaw from below and around the edges. Cracks race across the frozen layer. The solid sheet splinters into floating ice panels, some stretching tens of meters wide.

These thin sheets now float on the shallow water. Some rocks become embedded, while others position themselves in front of drifting ice panels, setting up for the next critical moment.

There is no dramatic storm, nor a roaring wind. Instead, sunlight quietly warms the surface, breaking the ice apart and leading to the next step.

Light Wind Pushes the Ice And the Stones

The final piece of the puzzle is wind, but not extreme wind.

During the documented movement events in December 2013, wind speeds were recorded at only about 3 to 5 meters per second, roughly 7 to 11 miles per hour. That is a steady breeze, not a desert gale.

On dry ground, that breeze would be too weak. But here, wind pushes the broad, floating ice panels, which act like sails, transmitting the force. As the ice drifts, it gently presses against the rocks, setting them in motion.

Because the stones rest on wet, slick clay, resistance is low. The rocks begin to slide, slowly at first, sometimes just a few feet per minute. Over several hours, they can travel dozens or even hundreds of meters, carving smooth tracks into the soft surface. Each phase leads naturally to the next.

GPS devices attached to several stones confirmed movements of more than 200 meters during multiple events. Time-lapse cameras captured the gradual motion in real time.

The rocks do not roll or tumble. They glide.

Why It Rarely Happens

This remarkable sequence relies on precise timing to unfold smoothly from one stage to the next.

There must be enough rain to flood the playa, but not so much that rocks float. Overnight temperatures must fall below freezing to form thin ice, but not stay cold long enough to make thick, rigid sheets. The following day must bring sunlight to weaken and break the ice. The wind must be steady yet moderate.

If any one of these conditions fails, nothing moves.

This explains why visitors returned for decades without seeing the motion itself. The tracks last for years, but actual movement is rare and depends on all steps aligning.

From Speculation to Proof

The breakthrough resulted from linking data with careful observation. Researchers installed a weather station to track temperature and wind, placed GPS trackers on selected rocks, and recorded continuous imagery across the playa, stitching together the story of the stones' movements.

On December 21, 2013, as ice broke apart around midday, cracking sounds echoed across the frozen pond. Shortly afterwards, the stones began sliding slowly across the wet surface.

There were no mysterious forces involved, nor were extreme winds needed.

Just a rare alignment of shallow water, thin ice, sunlight, and a gentle breeze.

In a landscape known for heat and dryness, ice turned out to be the quiet force that makes stones sail across the desert floor.