National Park of Great Sand Dunes

Location: Colorado
Established: September 13, 2004
Size: 107,000 acres (43,301 hectares)

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 (3,960-meter) 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 (230 meters) 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 (48 square kilometers). 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 (64 kilometers) 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 (3,960 meters). 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.