Rocks often moved multiple times before reaching their final resting place. The researchers also observed rock-less trails formed by grounding ice panels —features that the Park Service had previously suspected were the result of tourists stealing rocks. Richard and Jim Norris, and co-author Jib Ray of Interwoof started studying the Racetrack's moving rocks to solve the "public mystery' and set up the "Slithering Stones Research Initiative" "Science for the fun of it" to engage a wide circle of friends in the effort.
They needed the help to repeatedly visit the remote dry lake, quarry rocks for the GPS-instrumented stones, and design the custom-built instrumentation. Ralph Lorenz and Brian Jackson of the Department of Physics, Boise State University , in contrast, started working on the phenomenon to study dust devils and other desert weather features that might have analogs to processes happening on other planets.
But we have not seen the really big boys move out there Death Valley National Park wants to remind people that the Racetrack is located in a remote area of the park and road conditions are variable at best, requiring high clearance vehicles and heavy duty tires.
Do not attempt a trip to the Racetrack without a plenty of fuel and water. There is no cell phone service in the area. Be prepared for the possibility of spending the night if your vehicle becomes disabled. A more easily-accessible location to observe the tracks of sliding stones is the Bonnie Claire playa east of Scotty's Castle--between the park boundary and Highway The south shore of the playa runs right along the north side of Highway The area is administered by the Bureau of Land Management.
There is abundant evidence of sliding stones at this playa, which is believed to experience the same rock-moving conditions as the Racetrack.
Please Help. The surface of the playa is very fragile. Driving on it or anywhere off established roads is prohibited. Do not move or remove any of the rocks. When the playa is wet, avoid walking in muddy areas and leaving ugly footprints.
This prevents others from enjoying this unique area. Box Death Valley , CA Explore This Park. Info Alerts Maps Calendar. Alerts In Effect Dismiss. Dismiss View all alerts.
The Racetrack. Mysterious moving rocks. Jeffery Aiello Nestled in a remote valley between the Cottonwood and Last Chance Ranges, the Racetrack is a place of stunning beauty and mystery. The Racetrack is a playa--a dry lakebed--best known for its strange moving rocks. Caution: Rough and Remote Road The road to the Racetrack is rough, and good tires, 4x4 and high clearance are usually required.
What causes these rocks to move? Researchers just recently found out. Remote observations from to 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. The only period with observed conditions comparable to those during which we have presently observed rock motion is February, 10—15, [12].
A single, small trail was suspected to have formed during that season [11]. A persistent pond can support multiple movement events; our GPS instrumented rocks have recorded at least two separate move events with total trail lengths for a single stone of up to m Table 1. Our weather station adjacent to the playa recorded multiple nighttime freezing events and subsequent episodes of sustained daytime winds of 3. The fresh appearance of many of these trail segments formed by one rock likely reflects the short period days or weeks between rock movements rather than movement events separated by many years.
Likewise, changes in wind and water flow vectors between different days can explain the often high angle turns between different trail segments created by a single stone. A surprising finding is the power of even thin sheets of ice to move large stones, without buoyant uplift [15] , [16] , [17].
Rock movement on Racetrack Playa is similar to the movement of rocks in deeper lakes and marine basins where ice break-up is a regular spring phenomenon. For example, the ice-driven movement of rocks, including large boulders, is known to produce rock trails on the shallow bottom of the Great Slave Lake in northern Canada [19] and the shores of the Baltic Sea [20].
Ice is also likely to explain rock trails over usually dry lake surfaces in Spain [21] and South Africa [22] where relatively high elevation and cold winters contribute to the formation of floating ice. A necessary condition for the rock motion we observed is the existence of a playa pool deep enough to submerge the southern section of the playa, yet shallow enough to leave many rocks partly exposed at the pond surface.
Other repeating features of rock movement events that we observed include the presence of floating ice, temperatures and sunlight sufficient to create melt pools in the ice, and light breezes that are steady enough to drive floating ice. Although the ice breaks up around rocks, even thin moving ice sheets can generate sufficient force to drive rocks across the pool. All observed rock movement events occurred near mid-day when sufficient ice melting had occurred to allow ice break-up.
Creation of rock trails is difficult to observe because trails form below the ice-covered pool surface where they are often not evident until the ice has melted, and liquid water has been removed. Therefore, the extremely episodic occurrence of rock motion years to decades is likely due to the infrequency of rain or snow events sufficient to form winter ponds. Data period: Nov to Jan Records of hour-total rainfall column 2 , as well as hourly average insolation column 3 , air temperature column 4 , and wind velocity column 5 with the time stamp given in column 1.
The record of maximum wind gust strength in column 7 is calculated to the nearest minute with a time stamp given in column 6.
Station located at N Instrument package specifications reported in the text and table header. Data obtained for three rocks A3, A6, and A11 that recorded position and velocity. Rocks A3 and A6 had total trail lengths longer than recorded by their GPS instrument packages Table 1 , showing that they moved at least one more time after their GPS batteries had been depleted.
GPS instrument packages are custom designed units by Interwoof. RDN and JMN shared equally in the conception of the study, interpretation of the phenomenon, and drafting of the text.
RDL and BJ contributed to interpretation of the phenomenon and writing of this manuscript. Callahan for his assistance in setting up the experiment. Thanks also to R. Crane and M. Hartmann for assistance during equipment service and deployment visits.
Interwoof provided support in the form of authors' salaries and research materials. NASA provided support in the form of salaries for authors RDL and BJ , but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The Commercial Firm Interwoof likewise provided salary support to JMN and JR for the study, but did not otherwise play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.
National Center for Biotechnology Information , U. PLoS One. Published online Aug Richard D. Norris , 2 Ralph D. Lorenz , 3 Jib Ray , 2 and Brian Jackson 4.
James M. Ralph D. Vanesa Magar, Editor. Author information Article notes Copyright and License information Disclaimer. Received Mar 20; Accepted Jul This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
This article has been cited by other articles in PMC. Abstract The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the s. Introduction Racetrack Playa in Death Valley National Park, is well known for the phenomenon of tracks left by hundreds of rocks plowing across the nearly flat playa surface Fig. Open in a separate window. Figure 1. Time lapse images of a moving rock.
Figure 2. Methods To describe the meteorological conditions on the playa and the velocities and timing of rock motion we installed a weather station adjacent to Racetrack Playa, several time lapse camera systems overlooking the southeast corner of the playa [9] , and 15 GPS-instrumented rocks on the playa surface Fig.
Figure 3. Map of Racetrack Playa. Figure 4. GPS-instrumented rock with its rock trail. Table 1 Characteristics of GPS-instrumented rocks.
Rock mass kg , starting position, ending position, and total length of movement m for eight of 15 GPS-instrumented rocks. The other seven rocks in the deployment did not move, or were not recovered by the time of manuscript submission.
Rocks A3, A6 and A11 recorded their position and velocity during their initial movements as reported in Table S2. Rock A11 positions are recorded from its internal GPS unit. Figure 5. Figure 6. GPS-instrumented rock trajectories and velocity. Figure 7. Error analysis of GPS-instrumented rock movement events. Figure 8. Racetrack Playa phenomena. Figure 9.
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