Sand grains are moved up the gentle windward slope, and accumulate on the steeper downward side. There are several different types of dunes. The four main types are barchan, longitudinal, transverse, and parabolic, though there are many intermediate types. Barchan dunes are crescent shaped with the tips pointing downwind. They form in flat areas with little vegetation, and a limited supply of sand.
Longitudinal dunes form long parallel ridges, aligned parallel to the prevailing wind.
Transverse dunes form long ridges perpendicular to the prevailing wind direction. They form where sand is abundant, and vegetation is rare. Parabolic dunes are crescent shaped, with the tips pointing upwind. They are common in coastal areas where sand is abundant, the wind is strong, and vegetation provides some cover. Coppice dunes can be found throughout the Las Cruces area.