Strange Sailing Stones of Death Valley
Photo by Tahoenathan.
Licensed under the Creative Commons Attribution-Share Alike
3.0 Unported license.
In this mysterious and desolate corner of the California
desert, the stones move by themselves.
There is no doubt that California's Death Valley
National Park is an unusual place. Situated in the Mojave Desert,
it is the driest location in North America. With one spot at 282
feet (86 m) below sea level, it also has the distinction of being
the lowest elevation of any place on the continent. Finally, it
also known to be the hottest locale on Earth with temperatures
hitting a record high of 134 °F (56.7 °C) in the Furnace Creek
section of the park.
While all these features are certainly unusual,
there is one more oddity about Death Valley that makes it one
of the strangest places in the world. It's a place where the rocks
move by themselves.
Now you might argue that there are plenty of places
where rocks move without human or animal intervention. During
an avalanche, tons of mud, soil and rocks can come tumbling down
steep slopes. And during an earthquake, even large boulders can
go bouncing around. In Death Valley, however, these stones slide
across a nearly-flat, dry, lakebed called Racetrack Playa leaving
long, smooth tracks. No avalanches or earthquakes needed. Not
just little stones either. Some of the moving rocks are estimated
to weigh as much as 700 pounds (318 kilograms).
What's even stranger is that some rocks seem to
move in long straight lines, then suddenly change directions.
Others look like they've taken a smooth, curved path. Some of
the tracks made by the stones are just a couple of yards long,
while others run hundreds of feet.
Rock travel on a straight line, then make a sudden sharp
turn. (Photo by Jon Sullivan in Public
The lakebed is very isolated and rarely visited
by people. Nobody has ever been there at the right time to actually
see a rock in motion. Because of this, over the years a number
of odd theories have been developed about what might be behind
the phenomenon. Some of the ideas include magnetism, mysterious
energy fields and even pranksters. Some of the more extreme solutions
involve flying saucers and aliens.
Take an Interest
The strange phenomenon was first documented in 1915
when a prospector named Joseph Crook from Fallon, Nevada, visited
the area. Crook observed that some of the stones sitting on the
lakebed were at the end of long "tracks," giving the impression
that they must have moved, scraping up a little less than an inch
or so of the soil as they crept along.
In 1948 two geologists, Jim McAllister and Allen
Agnew, published the first scientific report of the phenomenon
in the Geologic Society of America Bulletin. The two suspected
that high winds and wet, slick mud on the lakebed might be behind
the odd movements. It also occurred to them that if the effect
was due to conditions on the valley floor, they might find rocks
that do the same thing in other locations. A similar phenomenon
was found to be happening at Little Bonnie Claire Playa in Nye
County, Nevada, and later on at Great Slave Lake, in Canada's
In 1955 George M. Stanley looked into the mystery.
He thought that the stones were too heavy to be moved by the wind
alone. He suggested that at times the dry lakebed would flood
and if temperatures were low enough, the water would turn to ice.
As these ice sheets moved, they would carry the rocks they trapped
along with them.
It wasn't until 1972, however, that somebody decided
to test Stanley's theory. Researchers Bob Sharp and Dwight Carey
went to the valley and picked thirty stones for their test which
looked like they had moved in the recent past. They gave each
of the stones names and placed stakes in the ground near them
to mark their current locations. They then picked a few special
stones and created a corral around them using metal stakes made
of rebar. The idea was that if a large ice sheet was involved
in moving the stones, they would be blocked or deflected by the
stakes of the corral. The stones seem to take no notice of the
corral, however, and one of them left it that winter only narrowly
missing one of the stakes on its way out.
This seemed to indicate that if ice was involved,
it was just a small collar of ice around the stone itself, not
a large sheet. One of the other things that came out of the seven
year study was the observation that none of the stones seemed
to move in the summer. Only during the winter.
rocks can follow and curved course. (Photo
by Tetraktys. Public Domain)
During the study 28 of the 30 stones originally
selected for monitoring moved. The smallest stone (named Nancy)
which was only a few inches across, moved the longest distance:
860 feet (260 m). The largest stone to move weighed about 80 pounds.
One of the heaviest stones, Karen, which was estimated to weigh
700 pounds, did not move at all.
However, after the test period was over, Karen disappeared.
It was rediscovered by San Jose geologist Paula Messina in 1996
about a half mile from its last known location.
In 1995 another scientist, Professor John Reid,
and several of his students went to Racetrack Playa to examine
the mystery. They found evidence that despite the research done
in the seventies at least some of the stones were moving due to
being embedded in a large sheet of ice (up to half a mile wide).
They based their conclusions on the marks found on the ground
after the winter of 1992-1993.
However, there is confirmation that the stones can
also move individually. In 2011 a study suggested that the dry
lakebed can flood, then freeze. As the water thaws, ice may cling
to the stones, floating them like little icebergs. Partly floating
in the water with ice to reduce the friction, a strong gust of
wind can get even a very heavy stone moving. Once a stone is on
the move, the energy it needs to keep going is only half of what
is needed to get started, so they can continue for quite a distance
even if the wind gust drops.
In 2006 Ralph Lorenz, a NASA scientist, developed
a tabletop experiment that seemed to confirm the idea of "ice
rafts" floating and moving the stones. He was first drawn to the
sailing stone mystery because he was interested in meteorological
conditions on Saturn's moon of Titan and Racetrack Playa seemed
to have some very similar characteristics.
Lorenz put a rock into a Tupperware container and
then filled the container with water until the rock was almost
covered. He then froze it and let it thaw out a bit until there
was just a small raft of ice with the rock caught in it. He then
put the rock with its "ice raft" into a tray of water with sand
at the bottom. The ice floated the rock so that it only lightly
sat on the bottom. Lorenz could then blow on the rock and it would
move easily across the sand, leaving a trail behind it.
Scientists would like to confirm the stones' movements
by the use of inexpensive time-lapse digital cameras, but so far
it's a difficult task to catch the rocks in the act. It is believed
that a single stone might not move for years and when it does,
the movement might only last about 10 seconds.
Thus though there seems to be a logical mechanism
for the movements of the stones, nobody has actually ever seen
it happen. So we still can't disprove that it isn't just the result
of a group of extraterrestrials out to play a prank on us humans
Racetrack Playa is a flat, dry lakebed in Death Valley National
Park. (Photo by Steven Norquist licensed
under the Creative Commons Attribution-Share Alike 3.0 Unported
Copyright Lee Krystek
2014. All Rights Reserved.