Moving Rocks in Death Valley

In Death Valley, California, there’s a dry lake called the Racetrack Playa or simply, “The Racetrack,” which is famous for its moving rocks. These “sailing stones” leave tracks across the playa like cars around a racetrack, and no one knows exactly why. They move only once every two or three years, and they’ve never been filmed in motion.

So how can rocks move? One theory is that the stones move in winter when it has rained enough to make the clay on the playa slippery. The winds in the desert, which can reach 145 kph, then push the rocks across the ground. Another theory is similar: when there’s enough rain in winter, a thin layer of ice forms when the desert temperatures fall below freezing at night. The wind then pushes the rocks across these ice sheets. Recently, a third theory has been proposed that ice actually forms around the rocks when the local water level rises. The rocks can then move even with light winds.

Other playas in Death Valley have similar rock patterns, but The Racetrack is unique because it has more rocks and longer grooves, meaning that there are plenty of places to find and photograph these incredible patterns.

Sources : wikipedia & Images from google.com