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How a Sand Dune Forms Sand dunes form wherever there’s constant wind and sand. The size of a


dune depends on how much sand there is in an area. The shape of a dune depends on the direction and force of the wind.


BARCHAN DUNES “Barchan” is the Turkish word for “crescent- shaped.” This type of dune is found on the edges of sand seas. It’s formed when the wind blows steadily in one direction.


Crest


Windward side


Leeward side


Direction of the wind


SEIF DUNES Long rows of sand dunes are named after the Arabic word for “sword.” These form when the wind blows from two sightly different directions.


Direction of the wind


STAR DUNE Multi-armed, star-shaped dunes form in areas with a lot of sand and seasonally changing winds.


Direction of the wind 21


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