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Ice Rafts Not Sails: Floating the Rocks at Racetrack Playa
American Journal of Physics (2011)
  • Ralph D. Lorenz, Johns Hopkins University
  • Brian K. Jackson
  • Jason W. Barnes, University of Idaho
  • Joe Spitale
  • John M. Keller
We suggest that the existence of many of the rock-carved trails at Racetrack Playa in Death Valley National Park is predominantly due to the effect of arbitrarily weak winds on rocks that are floated off the soft bed by small rafts of ice, as also occurs in arctic tidal beaches to form boulder barricades. These ice cakes need not have a particularly large surface area if the ice is adequately thick—the ice cakes allow the rocks to move by buoyantly reducing the reaction and friction forces at the bed, not by increasing the wind drag. The parameter space of ice thickness and extent versus rock size for flotation is calculated and found to be reasonable. We demonstrate the effect with a simple experiment.
  • ice,
  • drag reduction,
  • friction,
  • ice sheets,
  • aerodynamics
Publication Date
January, 2011
Publisher Statement
Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in the American Journal of Physics, volume 79, issue 1, and may be found at doi: 10.1119/1.3490645
Citation Information
Ralph D. Lorenz, Brian K. Jackson, Jason W. Barnes, Joe Spitale, et al.. "Ice Rafts Not Sails: Floating the Rocks at Racetrack Playa" American Journal of Physics Vol. 79 Iss. 1 (2011)
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