Flowing water that is not confined to a channel. Often over broad unconfined flat plains or dry lake beds. Sheetflow is thought to be responsible for the magical moving rocks of the Racetrack Playa in Death Valley National Park - which seem to move along the dry lake bed with no aid. In reality, sheets of water pick up the rocks and drag them across the lake bed, leaving trails that can last for decades.
The mysterious moving rocks of Death Valley NP are throught to be pushed by sheetflow.