A sandbox in the foot of the Rockies?
On my March 2015 road trip from Santa Fe, New Mexico, to Vashon Island in Washington State, I stopped at the Great Sand Dunes in southern Colorado, not far from the tiny, famous Crestone. When I turned off Rt. 17 to drive the 20 miles of narrow road to the dunes, informative signage said, “¡Bienvenidos! Caminantes!” Welcome Walkers! Of course, we’re drivers now, but two centuries ago, it was walkers and riders who encountered the Dunes.
There’s a geological oddity there in Colorado—a massive sand pile, the tallest in North America, backing up to the 13,000 snow-covered peaks of the Sangre de Cristo mountain range. It’s a US National Park and Preserve since 2004, and on the warm winter day in March that I visited, locals and tourists turned out to pretend they were on an oceanside beach, having picnics and building sand castles.
But what caused this formation in the middle of the high desert of the San Luis Valley at the end of the Rockies?
The short answer is that the sand dunes were formed from the erosion of glaciers by the Rio Grande and its tributaries. Over the course of the last 440,000 years, the wind picked up sand from the river’s vast valley and, unable to lift the granules over the high Rocky mountains, it deposited them—grain by grain—in the pile that we see as these beautiful dunes. The mountains of sand are said to be growing still, and they change daily.
At certain times of the year—like when winter turns to spring—water streams down from the surrounding mountains and flows past the dunes. Visitors simply wade into the shallow Medano Creek, cross the stream, and then hike up the dunes as fast and as far as they want. I saw a sign that said something like “Wander where you wish” and felt grateful that at least in this National Park there did not appear to be a huge number of restrictions.
There’s an accommodating Visitor Center and gift/book shop, staffed by people eager and willing to tell all about this unusual natural monument. In addition, in that shop, there’s considerable emphasis on the Native and early Spanish history and culture in the region (where the river was first known as the Rio Bravo del Norte), as well as plenty about the “American” pioneers who settled ranches and farms in the area.
This place is well-worth a visit, especially if you have children.