White Sands — The Largest Gypsum Desert in the World
Near Alamogordo, New Mexico
West of Alamogordo, the floor of the Tularosa Basin holds one of the strangest landscapes in North America. The White Sands dunefield is the largest gypsum desert in the world, covering about two hundred seventy-five square miles of the basin floor in brilliant white dunes that shift and ripple in the wind and reflect so much sunlight that the surface is difficult to look at directly in the afternoon. The white mineral is gypsum, calcium sulfate dihydrate, the same material used to make drywall and plaster.
It came from the surrounding mountains, dissolved by rain and snowmelt, and carried by rivers into the enclosed Tularosa Basin, which has no outlet to the sea. As the water evaporated over tens of thousands of years it left the mineral behind in increasing concentrations. The process continues today.
Lake Lucero, a dry lake on the western edge of the dunefield, periodically floods during wet seasons and then evaporates, depositing fresh gypsum crystals that wind and erosion eventually break into sand grains and blow eastward into the main dunefield. White Sands was established as a national monument in nineteen thirty-three by President Herbert Hoover and elevated to national park status in two thousand nineteen. It is the second national park in New Mexico, after Carlsbad Caverns.
The park is sometimes closed for hours at a time when missile or rocket testing is underway at the surrounding White Sands Missile Range. Signs at the entrance warn visitors that the road may close without notice.
