SAILING STONES, SLIDING ROCKS & MOVING ROCKS, all refer to a GEOLOGICAL PHENOMENA, where rocks, known to be weighing 700lbs. move and inscribe long tracks, along a smooth valley floor, UNAIDED BY GRAVITY, and human and animal intervention.
The rocks move only every 2 or 3yrs. and most tracks develop over 3 or 4yrs. Rocks, with rough bottoms leave straight, striated tracks, while those with smooth bottoms, tend to wander. Rocks, sometimes, turn over, exposing another edge to the ground and leaving a different track —— in the rock’s wake.
Trails differ in, both, direction and length. Rocks that start next to each other, may travel parallel, for a time, before one abruptly changes direction —– to the left, right or even back to the direction from which it came. Trail length also varies. —- 2 similar-sized and shaped rocks may travel uniformly, then one could move ahead or stop in its tracks.
Tracks of SAILING ROCKS have been observed or studied in various locations and, most notably, in the DEATH VALLEY NATIONAL PARK, California, where the number and length of tracks are notable. These tracks have been studied since 1900s, yet the origins of STONE MOVEMENT have not been confirmed. However, as of August, 2014, time-lapse video footage of ROCKS MOVING, has been published, showing the rocks moving at low-wind speeds within the flow of thin, melting sheets of ice or WINDOW-PANES of ICE, and thus identified the cause of the sailing stones to be ICE SHOVE, which pushes rocks up to 5mts per minute.
According to Huffington Post, researchers from John Hopkins university, have now determined that the rocks move only under a specific set of conditions. First water must flood the area at a level just deep enough for the bases of the rocks to be surrounded by a thin WINDOW-PANE of ICE. If these PANES are big enough, even a light wind is enough to move the ICE-RINGED ROCKS. Once, in motion, the rocks move in fits and starts, sometimes making abrupt changes in direction as the wind shifts.