RATING: ♦♦♦♦♦
One of its kind in all the world! About 60 miles north of Las Cruces is one of the world’s great natural wonders – the white sands of New Mexico. Great wave-like dunes of gypsum sand have engulfed 275 square miles of desert, creating the world’s largest gypsum dune field.
Gypsum rarely occurs as sand because it is water-soluble. Rain usually dissolves gypsum and rivers then carry it to the sea, but the area of White Sands is a basin that has no outlet to the sea. Rain that would normally dissolve the gypsum is trapped and either sinks into the ground or forms shallow pools that subsequently dry out, leaving gypsum on the surface in a crystalline form called selenite. During the ice age, a lake now called Lake Otero covered much of the basin. When it dried out, a large flat area of selenite crystals remained, which is named the Alkali Flat.
The selenite crystals on Alkali Flat measure up to three feet thick. Weathering and erosion eventually break the crystals into sand-size grains that are carried away by the winds, forming the white sand dunes. The dunes constantly change shape and slowly move downwind.
Unlike dunes made of quartz-based sand crystals, the gypsum does not readily convert the sun’s energy into heat, so it can be walked on safely with bare feet, even in hot summer months. Four marked trails allow visitors to explore the dunes by foot. Totally worth it to walk the dunes. It’s like being in another world.
At the visitor center, we learned about the plants and animals in this area that have evolved in ways that have allowed them to survive in the dunes. We have a photo of a small lizard that has turned white to blend into the dunes. It’s almost impossible to see in the picture, without the black circle.
White Sands National Monument is completely surrounded by military installations, the White Sands Missile Range and Holloman Air Force Base. For safety reasons, the area is closed to visitors during missile testing. Tests occur about twice a week on average, for a duration of one to two hours.
