How does a sande dune form?

Answer 1

Sand particles can be carried away by strong winds. These particles eventually fall when the wind if not strong enough to keep them aloft.

Sand dunes form in areas where wind routine occurs. The dunes start when an obstruction of some sort acts as a barrier to block the wind. The wind slows down when it hits the barrier, allowing the sand particle to fall to the ground Eventually, the obstruction, which may be a stump or rock, will become completely buried by sand. The dune continues to grow by the same process as more and more sand particles are released by the winds that slow down when they hit the dune.

Interestingly, dunes move slowly. This occurs when the wind lifts sand up on the windward side and the sand falls down on the leeward side.

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