The Sailing Stones of Death Valley
Simply Unexplainable 11/24/09
By: Chris Capps
Ever since they were first discovered, the legendary Sailing Stones of Death Valley have inspired those who have seen them to scratch their heads in wonderment at one of mother natureÃ¢â‚¬â„¢s most perplexing mysteries. What could possibly make stones, some as heavy as 250 lbs move by themselves?
The stones reside in Death Valley, the lowest point below sea level in North America, hanging as low as 282 feet. Interestingly enough Mount Witney, the highest point in in the Contiguous United States is merely 76 miles away. The climate is arid and dry, with winds moving sometimes at up to 90 miles per hour.
Some scientists have speculated that the phenomenon is easy enough to explain. They say the winds combined with a thin sheet of ice over the surface of the sands create an easy sliding track for the strong winds to push the rocks across. As the stones are pushed, they create deep furrows in the ground behind them. High winds normally are not enough to move massive boulders, but in this case the ice makes for a smooth track making it quite literally a breeze to move the stone hundreds of feet per night.
Most of the stones exist within an 850 foot hillside and are made of dolomite, an intrusive igneous rock. Often the sides and bottoms of the stones are sheer. According to the official theory, the conditions required for the stones to move are a water enriched surface not flooded over, but rather saturating the clay beneath the stone, a thin layer of clay beneath the stone, very strong winds maintaining a constant direction for many minutes, and the terrain must be level nearby the dolomite.
Geologists Bob Sharp and Dwight Carey began a program in 1972 to monitor the stones. By staking and tracking the movement of the stones, they were able to discover up to 30 unique stones and their movements over the course of several months. The two discovered, however, that often the stones would move in different directions, often in opposite directions even from one another. The wind explanation therefore has been called in to question.
It was not until 1995 that physicists finally came up with an explanation that solved the problem. Just above the ground winds slow due to interactions with the rough texture of the ground. These areas are known as boundary layers. Stones no more than a few inches high would be under the intense and compressed force of ambient winds, which can gust at up to ninety miles per hour in winter during storms. ItÃ¢â‚¬â„¢s similar to how a ship sails. The initial burst is the most difficult as it requires a great deal of momentum to get the vessel moving, but a continuous wind makes gives the forward momentum required to keep it moving.
Is it merely wind that pushes these rocks along? Though compelling evidence seems to point in both directions in regard to this phenomena, this does not dispel how incredibly enchanting the rocks must be as they move by unseen hands across the desert floor of one of the most uninhabitable places in the world.