These sediments contain sand, pebbles, rocks, and even boulders. This force of water washes away the top layer of soil and erodes the rocks, leaving behind a layer of hard dry land. These floods continue to move through the land, tearing away rocks and cutting new channels in the land, which produce swift running streams. Through evaporation, these streams eventually vanish, leaving behind deep grooves in the land, and sediments of salt and other minerals. These sediments build up and often form distinct shapes called alluvial fans .
Wind is also another important weathering agent in deserts.
Even though water is more powerful than wind, wind is still able to erode the land, and transport and deposit materials. Wind blows across the open spaces of the desert and picks up sand and other sediments. The force of the wind and sand then wears away, or erodes, the rocks in its path. When the wind loses its force and deposits its sand, dunes are formed. These dunes look like motionless waves .