When it comes to sand dunes in our region, we think of New Mexico’s White Sands, the Monahans Sandhills, or the Salt Basin Dunes near the Guadalupe Mountains. But there’s another great sand sea here.
South of Ciudad Juárez, just 40 miles from El Paso and the Rio Grande, the Samalayuca Dunes cover 55 square-miles. They have traditionally been known simply as Los Médanos – the dunes – and for centuries were a dreaded obstacle for travelers on the Camino Real. Now, they’re a protected area and park. These dunes are distinctive in their history, and their beauty.
Dr. Richard “Rip” Langford is a geology professor at the University of Texas-El Paso.
“When I first came to El Paso,” Langford said, “there were a lot of features along the border here that just never had been studied, one of which was this huge lake, three times larger than Lake Otero, a pluvial lake called Lake Palomas.”
Langford’s interest in the Samalayuca Dunes began 20 years ago. With two colleagues, he recently published a paper exploring their geology.
It’s a scientific irony, Langford said: Desert dunes are the definition of aridity, yet they owe their existence to bodies of water.
Early geologists quickly realized the Southwest once looked quite different. In the lusher climate of the Ice Age, what are now desert basins were great lakes. Lake Bonneville was among the largest. A fraction of it remains as Utah’s Great Salt Lake. And our region too had such lakes: Lake Otero in New Mexico’s Tularosa Basin, Lake King beneath the Guadalupes.
Then, there was “Paleolake” Palomas. It spanned 3,500 square miles, mostly in what’s now Chihuahua. Multiple rivers – the Rio Casas Grandes, the Rio del Carmen, the Mimbres River – emptied their waters here.
Lake Palomas rose and fell for millennia. But, as desert conditions took hold, it finally vanished about 9,000 years ago. Since then, dry winds have scoured the empty lakebed. Dust from Lake Palomas affects air quality as far away as Canada.
But not all that dust escapes. The lakebed is hemmed in by mountains, including the high wall of the Sierra del Presidio.
“And the wind has to lift to go over those mountains,” Langford said, “and when it does, the sand can't come with it. And so it got all piled up against, well, not against the mountains, but about a couple of kilometers upwind of the mountains.”
It’s gypsum from an ancient lakebed that gives the White Sands their pallor. But the Palomas lakebed is mostly quartz, and the sands of Samalayuca are tan or golden.
Yet what truly sets Samalayuca apart are its dune forms. Winds here come not only from the west, but from the north and south. Forcing sands this way and that, these complex winds have created complex shapes, including immense “megastar” dunes.
“So you have 150-meter, 450-foot-high sand dunes that are really, really interesting,” Langford said. “And those form big conical pyramids of sand with arms that come out, which is why they're called star dunes. So these things are big, huge features.”
The Mexican federal government designated Samalayuca a protected area in 2009. Like other dunefields, Los Médanos are home to plants and animals found nowhere else. They’ve gotten the Hollywood treatment – in David Lynch’s 1984 version of “Dune.” And they’ve become a beloved playground for Juárez residents, a popular place for picnics, dune sledding and dune buggies.
They’re also an easily accessible day trip for West Texans, Langford said. An hour’s drive from El Paso, the Samalayuca Dunes are a magical part of the desert borderlands.
