Sand Dunes are big hill-like piles of sand or soil that get blown by the wind or can be impacted by other living animals. Sand Dunes form when a powerful wind sweeps up sand and soil and piles it up in a hill. Wind is very common in the desert because of the changing temperature between normal land and the desert. The wind blows the sand and soil into the wave-like shape. That is how a Sand Dune is formed! Sand Dunes can be affected very easily by outsider forces like animals, rain, or more wind.