Established: September 13, 2004
Size: 149,137 acres
Visitors to the Great Sand Dunes experience an undeniable sense of wonder, just as happens in so many of our most spectacular national parks. In contrast to the sudden shock of walking to the rim of the Grand Canyon, though, or topping a rise to view Crater Lake, the emotions evoked by this otherworldly landscape arrive in slow motion.
The dunes appear in the distance as you approach, but at first seem dwarfed by their backdrop, the 13,000-foot peaks of the Sangre de Cristo Mountains. Not until you're nearly at their border does their vast scale become apparent: dunes up to 750 feet tall, extending for mile after mile—an ocean of sand hills of breathtaking magnitude. That's just how the explorer Zebulon Pike described them in 1807: "Their appearance was exactly that of a sea in a storm (except as to color), not the least sign of vegetation existing thereon."
The dunes sprawl across part of southern Colorado's San Luis Valley, a broad, arid plain between the San Juan Mountains on the west and the Sangre de Cristos on the east. Streams and creeks flowing out of the San Juan Mountains over millennia carried gravel and sand into shallow lakes in the San Luis Valley. During drought periods, these lakes dried, releasing the sand particles to the action of the wind. Strong prevailing southwesterly winds carry the tiny grains toward the Sangre de Cristos, piling them up against the foothills. The resulting dunes are the tallest in North America, covering more than 30 square miles. Adults hike across them and marvel at their beauty; children run and slide down their steep faces, enjoying a playground of fairy-tale proportions.
Winds that often top 40 miles an hour continually reshape the crests of the tall dunes, and smaller dunes may "migrate" several feet in a week. The dunes show a remarkable permanence of form, though, which geologists attribute to opposing winds. Prevailing southwesterly winds blow the dune mass northeasterly toward the mountains, and occasional but powerful northeasterlies blow the dunes back toward the southwest. This 'back-and-forth' action of the wind piles the dunes vertically, and contributes to the stability of the dunefield.
The need to protect the water that protects the dunes has led to a number of changes at Great Sand Dunes. Through a cooperative effort among government agencies and private conservation groups, the purchase of private lands, identified as important to the protection of park resources, was completed on September 13, 2004. The new entity comprises the original national monument, lands west of the monument known as the Baca Ranch, and mountains east of the monument previously managed by the U.S. Forest Service. This latter realm was established as a preserve in 2000 to safeguard the small streams flowing into the area. Official designation is Great Sand Dunes National Park and Preserve.
All this means that visitors have access to a great diversity of habitats, beginning in the desert dunes, continuing up to the pinyon pines, cottonwoods, and aspens of the foothills, and arriving even higher at the spruce-fir forests and tundra of the summits of the Sangre de Cristos, with seven peaks over 13,000 feet. The region's geology and biology make it a fascinating place, unique among our national parks. It's well worth the drive across southern Colorado, even if all you do is gaze in awe at this extraordinary and lovely terrain.
How to Get There
From the east or north, take US 160 west from Walsenburg 59 miles to Colo. 150 and drive north 16 miles. From the south or west, take US 285 to Alamosa and drive 14 miles east to Colo. 150, continuing north to the monument and preserve. Airport: Colorado Springs.
When to Go
Year-round. Moderate temperatures make spring and fall best. The sand dunes can get very hot in summer, although they can be traversed comfortably early and late in the day; summer is also the park's most crowded season. Winter snow curtails trips into the high mountains, though the dunes can still be visited.
- Nat Geo Expeditions
How to Visit
Stop at the visitor center for a quick lesson in the Great Sand Dunes environment, and to learn the schedule of ranger-led walks and programs (summer only). From there, proceed to the dunes parking lot. Then walk out into the dunes, going as far and climbing as high as time and energy permit; the High Dune is a popular, moderately strenuous destination.
Kids and adults alike enjoy splashing along Medano Creek, which meanders along the base of the dunes (when there is enough water from the spring snowmelt). The Montville Nature Trail and the Mosca Pass Trail offer additional options for exploration, from short walks to mountain hikes.
If you have a high-clearance four-wheel-drive vehicle, and are very careful, you can drive the Medano Pass Primitive Road, which leads 11 miles up into the Sangre de Cristo Mountains in the national preserve, exploring different habitats along the way, from foothills to coniferous forest at the 9,982-foot pass.