29 April 2018

Brilliant White Sands

White Sands National Monument, New Mexico.

White Sands National Monument in southern New Mexico was stunning and exceeded my expectations. It will undoubtedly be one of the highlights of my trip through the Southwest this spring, made so in large measure because I was able to camp in the backcountry overnight.

The dunes are a brilliant white color due to being composed of gypsum (selenite) sand. They are remarkably cool to the touch, which is counter-intuitive for anyone who has spent time on a sandy beach in the warm sun. Because the sand was so cool and soft I was able to do some hiking in bare feet. The mineral composition of the sand (selenite is a hydrated mineral) and the relatively high water table in the dunes apparently help keep it cool.

The dunes are extensive, covering close to 300 square miles in a valley east of the San Andreas Mountains in southern New Mexico. A US military missile testing range is the Monument’s neighbor on three of its four sides, and sometimes the Monument closes because of missile activity.

Like coastal beach dunes, some of the gypsum dunes at White Sands had a modest cover of vegetation, while others were barren. Plants were more apt to be found in flat interdune areas that may provide longer-term stability from the vagaries of shifting sand. The most attractive flowering plant was sand verbena, with hemispherical clusters of light purple flowers. The only animal life I really saw was two species of beetles, though the Park Service made a point to illustrate that populations of animals (mammals, reptiles) inhabiting the dunes had adapted to become lighter in color than nearby populations which live in habitats with darker substrates.

Some dune vegetation, including a Yucca (or similar species), small trees that may be cottonwoods (Populus), and purple-flowered sand verbena.

 
Dune beetles.
Sunset over the dunes.
White Sands is a photographer’s dream, at least for the style of photography I am interested in. From the macro to landscape scales there were alluring subjects, curves, and shadows all around. I found the most compelling time for photography to be perhaps an hour or two before sunset and an hour or two after sunrise. During this period when the sun was low on the horizon, it cast beautiful shadows over the dunes and seemed to provide an ideal level of contrast. The white sand in the shadows in the early morning often appeared purple to me.

One feature of the dunes that I found particularly attractive was the parallel ripples, typically no more than a few centimeters in height over the dune surface. There are analogous undulations in coastal sand caused by water, and the ripples in the middle of this desert brought to mind the fact that air (wind) is like a fluid, acting to shape the substrate below it by its direction and strength of flow.

White Sands is certainly a park I would visit again, hopefully in the same fashion as this trip: sleeping under the moon and stars in a dunefield of sublime beauty.

Animal tracks.

Different ripple patterns on the surface of the dunes.

Shadows cast at a dune crest.
An interdune area with rougher texture, I suppose composed of selenite crystals.
Looking south over the dune field with the early morning sun casting shadows to the west.

My campsite and hiking barefoot in the dunes.


1 comment:

  1. Putting this on my list for my drive across country in a few weeks.

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