Las Cruces, New Mexico is located in the Chihuahuan desert. Naturally, many of the landforms around Las Cruces are typical of deserts around the world. These landforms are shaped both by wind, and by water.
It is often assumed that wind is the most important erosional agent in the desert. While wind does contribute to erosion, it plays a much more important role in sediment deposition. The most well known wind formed sediment deposits are sand dunes. Dunes are mounds or ridges of wind-deposited sand. As wind encounters an obstruction such as a boulder or bush, it must flow over and around the obstruction. Two zones of dead air are created in front of and behind the obstruction. Sand grains being transported by the wind are deposited in this area of dead air. The sand gradually accumulates; the sand itself becomes the wind barrier. Sand dunes are not fixed in place, they migrate in the prevailing wind direction. 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. These dunes form both along the mesas and in the Mesilla valley as well. These dunes are stabilized by the abundant mesquite trees in the area.
One of the best possible places to study sand dunes in action is located northeast of Las Cruces in the White Sands National Monument. There you can see the different dune types in a vast expanse of gypsum sand deposited after an ancient lake evaporated.
Another wind formed land feature is desert pavement. Desert pavement is formed when the dried soil is constantly blown out by the wind, leaving heavier material behind. The result is a ground surface composed mainly of pebbles and cobbles.
Water plays a very large role in the formation of desert landforms. Rainfall in the desert occurs most often in brief but intense cloudbursts. The ground cannot absorb all of the water dumped on it in such a short time. As a result, the excess water erodes the landscape in the form of flash floods. Normally dry stream channels, or arroyos, are filled with mudflows and muddy waters; transporting and depositing large amounts of sediment.