Photos of the "Sailing Stones" on the Racetrack dry lake in Death Valley (California)
The "Sailing Stones" are rocks that move in long tracks along the smooth and perfectly flat surface of a dry lake, without human or animal intervention.
The best time to take photos of the sailing rocks and their tracks is just before sunset, or just after sunrise, when the light is grazing.
Those rocks move several hundreds feet every couple of years, during winter, but no-one has ever observed them moving. It is likely that the weather is extremely cold, wet and windy when the stones move, and by this type of extreme weather, no-one really wants to be there!
The rocks are most likely propelled by strong winds while entrapped in floating ice sheets (or icebergs), after winter rains flooded the dry lake and made the mud soft and slippery.
The natural process, as currently understood, involves:
1) heavy rain flooding the lake with a significant layer of water.
2) rain is followed immediately by below freezing temperature causing the water on the lake to freeze, entrapping the rocks in ice sheets.
3) more rain before the ice sheets melt, causing these ice sheets to float, The rocks are partially lifted by the icebergs that entrap them, reducing their apparent weight on the muddy bottom.
4) strong winds breaking the floating ice sheets and pushing them around, causing the entrapped rocks to move and leave tracks on the muddy bottom.
Because this combination of weather events is complex, it does not happen every winter.