Technically known as 'barkan', the "shifting sands" begin if there is sufficient dust on the ground and a unidirectional wind to blow it. The dust collects around a stone and begins to accumulate. The process continues, the mound grows until it is large enough and then it begins to move. The dune forms in the shape of a crescent with two sharp arms (on the right) pointing the way that the wind is blowing. |