Trail formation by ice-shoved "sailing stones" observed at Racetrack Playa, Death Valley National Park
Other literature type
Lorenz, R. D.
Norris, J. M.
Jackson, B. K.
Norris, R. D.
Chadbourne, J. W.
(issn: 2196-632X, eissn: 2196-632X)
Trails in the usually-hard mud of Racetrack Playa in Death Valley National
Park attest to the seemingly-improbable movement of massive rocks on an
exceptionally flat surface. The movement of these rocks, previously
described as "sliding stones", "playa scrapers", "sailing stones" etc., has
been the subject of speculation for almost a century but is an exceptionally
rare phenomenon and until now has not been directly observed. Here we report
documentation of multiple rock movement and trail formation events in the
winter of 2013–2014 by in situ observation, video, timelapse cameras, a
dedicated meteorological station and GPS tracking of instrumented rocks.
Movement involved dozens of rocks, forming fresh trails typically of 10s of
meters length at speeds of ~5 cm s<sup>−1</sup> and were caused by wind
stress on a transient thin layer of floating ice. Fracture and local
thinning of the ice decouples some rocks from the ice movement, such that
only a subset of rocks move in a given event.