Landform

Moving air can only transport sand and dust, and does not erode solid rock very effectively. Its characteristic landforms, sand dunes, occur in many sizes and shapes. Most have a gentle slope on the windward side, where sand is being eroded away, and a steeper leeward side, where sand is deposited. Movement of sand from one side to the other may result in the migration of the sand dune in the direction the wind is blowing. As with water, transport capability varies with velocity, so sand dunes often develop where the wind slows down. This is the case at Great Sand Dunes National Monument, Colorado, and Death Valley National Park, California, where spectacular, but localized, dune fields occur.