Great Sand Dunes National Park and Preserve protects 149,000 acres of dune field, transition zone, and a portion of the Sangre de Cristo Mountains in south central Colorado. The Park and Preserve was authorized by Congress in the waning days of the Clinton administration in 2000 and established in 2004 under the Bush administration. The dunes proper had received earlier protection in the waning days of the Hoover administration in 1932 after local communities became alarmed that the dunes might be destroyed for industrial use for gold mining or concrete production.
That the tallest sand dunes in North America rise above the enormous, flat, high-elevation (above 7,000 feet) San Luis Valley in Colorado—and not in, say Death Valley, nor the Mojave, Sonoran, or Chihuahuan Deserts, places generally much sandier than the valley—is a unique circumstance of geography. The sand that comprises the dunes comes mainly from the San Juan Mountains dozens of miles to the west across the broad, flat valley. Sediment washed down from the mountains by snowmelt, rain, and the Rio Grande, whose headwaters are in the San Juans and which begins its long journey to the Gulf of Mexico by emerging into the San Luis Valley. Sandy sediment is deposited on the western side of the valley and then blown by the prevailing winds rushing down from the San Juans. The Sangre de Cristo Mountains, the southernmost range in the Rockies, run north-south for 242 miles, but the dunes formed only in a nook just north of Mount Blanca, the range’s highest peak and a sacred mountain to a number of Native American peoples. The dunes formed adjacent to a relatively low saddle in the range where three major ephemeral springs flow down into the valley. The streams, which secure the sand, are important for the stability of the dunes and for the hardy plant communities that grow from the extensive sand flats surrounding the dunes proper. But it is the storm winds rushing down from the low saddle in the Sangre de Cristos that balance the prevailing winds from the west, keeping the dunes themselves remarkably stable over years and decades.
Even with the uniqueness of the region’s wind and geography, the sheer amount of sand cannot be explained just by this process. More recent evidence suggests that the southern end of the San Luis Valley was once covered by a vast lake, remnants of which are visible as wetland complexes west and south of the dunes and a vast aquifer beneath the valley, which makes agriculture possible. It is the sand of this ancient lakebed that comprises the bulk of the dunes.
Tuesday, August 24, we’d spend exploring this singular place by getting to know the transition area between the dunes and the mountains.
I woke up around 6:30, well before Sean did. I’d slept well for the first night back in the tent.
When I climbed out of the tent to walk over to the comfort station, the sun had not yet climbed high enough over the Sangre de Cristos to light the campground, but it was beginning to touch the highest points of the dunes.
In the chilly morning, I fussed about in camp. I love few things more than fussing about in a campsite. I made coffee and pre-prepped breakfast and read a bit while I waited for both the sun and my husband to join me.
Sean emerged from the tent into a campsite bathed in sunlight. I fixed him a campground version of an oak milk latte, and we ate our “Breakfast Skillet” burritos, our classic and by-far favorite campsite morning meal.
We weren’t the only ones up and about. Jays, Ravens, and an array of little brown birds were busy in the campground.
After breakfast, we gathered up our day packs, tidied our campsite, and set out on our first hike.
We wanted to get the lay of the land, and so we chose to begin with the Dune Overlook Trail, which started from the campground close to our site. The trail winds for a mile through the transition zone between the dunefield and the slopes of the mountains, ending at an overlook with commanding views.
Dune Overlook Trail, which for its first two-thirds doubles as the much longer Sand Ramp Trail, really is wonderful. If you visit Great Sand Dunes and have time for only one hike, do this one because it gives a bit of everything the park offers: dunes, mountains, and a unique ecological community.
The mix of grasses, sage, and shrubs the trail traverses are similar to other plant communities in the San Luis Valley and in the general region, but here they persevere in soil that is extremely sandy. In addition to the fine-grained sand from the dunes, which originates in the San Juans, there is also a course-grained sand here, which has been swept by wind and water down from the Sangre de Cristos. By and large, if the grains are fine, they have bounced and blown over from the San Juans. If they are course, they have more recently washed down from the Sangre de Cristos.
The trail dropped us into a shallow ravine where trees, as opposed to shrubs, were clustered.
Because of the presence of water, it suddenly got very buggy, with swarming mosquitoes. We moved through quickly.
We reached the fork where the overlook trail separates from the Sand Ramp Trail, which continues on for some twenty miles with multiple backcountry campsites along the way.
Dune Overlook Trail, though, switchbacks gently up a ridge to the overlook.
As is usually the case, the higher we climbed, the better the views became.
Up at the overlook, which faced west, there were a couple of benches waiting for us. Between the campground and the overlook, we’d passed no other hikers.
Facing northwest, it was easy to see the transition between dunes into mountains. The flat, light green expanse in the image above is the sand flat area where tenacious plants grow in soil more sand than anything else. The ribbons of dark green indicate where streams and washes descending from the mountains provide enough moisture for shrubs and trees to survive.
From here we could see that the dunes themselves are not barren, but a couple species of grasses and even Prairie Sunflowers manage to survive on them.
It’s also a testament to the dunefield’s stability over time.
Below the outlook we could see the parking area at Point of No Return along the rough and sandy road at the base of the dunes.
High above, we could see hikers summiting High Dune, the highest dune easily accessible to the main visitor areas.
We had had the overlook to ourselves, and after half an hour decided it was time to head back.
As we descended, we passed a group of four senior hikers. They were relieved to hear that they were almost to the top and that there were benches available.
Back in the little ravine, we braved the mosquitoes to look at the butterflies, particularly the lovely Mourning Cloaks.
Sean pointed out little mounds of coarse sand that appeared to be the entrances to someone’s house. Probably Ground Squirrels.
There’s another one.
A cone attempted to dissuade hikers from using a social trail as a shortcut back to the campground.
All told, it was a pleasant hour-and-a-half of stretching our legs.
As we reached our campsite, we decided to just keep going, barely slowing down as we walked toward the other end of the campground and the trail to the Visitor Center.
We reached the trailhead and set out for the 1.3-miles, trending south.
Almost immediately, we spotted a Mule Deer buck with velvet still on his antlers.
He moved over to join two other bucks and a doe, who eyed us as we walked past.
This portion of the Park had experienced wildland fire at some point, and many of the junipers and piñons were standing dead.
Eventually, we glimpsed the Visitor Center in the distance and below us.
We reached Mosca Creek and the trail turn-off for Mosca Pass Trail, which climbs up to a saddle in the mountains. Saving that for later, we descended toward the Visitor Center.
We missed the actual trail and ended up briefly walking along the park road. Oh well.
The Visitor Center is a low-slung, adobe-inspired complex, which houses both the Visitor Center proper and some Park offices.
The main entrance was closed because of COVID-19, but the foyer had the National Park Passport stamp station and access to a water filling station and the restrooms.
Access to the gift shop and a limited portion of the Visitor Center was around back off of a broad porch area.
It was about 12:45 when we arrived, and the Visitor Center was closed until 1pm for a staff break. We sat and gazed at the view along with other waiting visitors. Occasionally, Broad-Tailed Hummingbirds whizzed by. They would be the species stuffed animal we’d bring home to represent this Park.
When the Visitor Center reopened, we lined up and were granted access up to a certain number. Then we were allowed in as other visitors left.
The interactive exhibits were either closed down entirely or else covered with protective sheeting. This was the biggest impact of COVID-19 that we experienced at the Park.
We planned to continue hiking, so we held off on making purchases. In the afternoon, we intended to climb up to Mosca Pass.