Thursday, April 30, 2020

High Dune and Star Dune

Dunefield from High Dune
7 miles loop, 1800 feet elevation gain
Difficulty: Moderate-strenuous
Access: Paved road to trailhead, Great Sand Dunes National Park entrance fee required

The Great Sand Dunes rise out of the flat San Luis Valley at the foot of Colorado's snowy Sangre de Cristo Range, a wondrous sea of silica that stand as the tallest dunes in North America. The massive dunefield is best appreciated while one is fully immersed within, making Star Dune and High Dune- two of the tallest dunes in the field- extraordinary vantage points to study this landscape. This is not a standard hike with a defined trail to follow; rather, it's a saunter, a voyage through an ocean of sand in which you more or less choose your own path and your own adventure. I'll give a general outline of the hike that I did, but know that there's many ways to reach Star Dune.

I hiked this trail on a blustery, cold February day after a major snowstorm the night before. Howling overnight winds had cleared most of the roads, but the northeast-facing aspects of hills had deep deposits of snow. From Alamosa, I followed US 160 east to its junction with Highway 150, which led along the base of the Sangre de Cristo Range to Great Sand Dunes National Park. I followed the road past the park entrance and the visitor center to a left turnoff for the dunes and a picnic area; I followed this spur road to its end at a parking lot along the wash of Medano Creek. While driving in, I had stupendous views of the dunes: Star Dune, the final destination of the day, was a particularly photogenic mountain of sand when set against the backdrop of the Crestone Needle, Kit Carson Peak, Cleveland Peak, and Mt. Herard.

Crestone Needle and Star Dune
I left the parking lot and crossed the sandy Medano Creek wash. In the morning, the wash was dry, with all nearby water locked up in ice by the below-freezing temperatures. By the time of my return that evening, snowmelt trickled through the wash. During the spring and summer during peak snowmelt, Medano Creek is filled with water and can exhibit a "surge flow" that resembles waves, making the area a popular inland beach destination.

Mount Herard and the dunes rise above Medano Creek
As I crossed the creekbed, I kept my eyes peeled on High Dune, the highest elevation dune in the dunefield and the sand pile directly across Medano Creek from the trailhead. Once across the creekbed, I wandered through a few of the shifting foothill dunes to reach the base of High Dune. I followed sand ridges uphill to ascend towards the summit of High Dune.

Ascending sand was less straightforward than I initially anticipated: for every step, my foot sank deep into the sand and my boots quickly filled with sand (gaiters are probably helpful!). Steep sand slopes were especially difficult to ascend: I simply slid down when trying to tackle dunes that were close to the angle of repose.

The climb up to High Dune
There was no trail: I simply followed what appeared to be the the clearest ridge towards High Dune and after a struggling over a mile I found myself atop the ridge of the dune. A short walk brought me to the summit of High Dune, where I had a sweeping view of the entire dunefield and of the Sangre de Cristo Range as well. To the north I could see all the way to the snow-covered Sawatch Range and to the west lay Star Dune, the San Luis Valley, and the San Juan Mountains.

Sangre de Cristo and the Great Sand Dunes, from High Dune
The Great Sand Dunes are born from the sandsheet in the San Luis Valley. Sandwiched between the Sangre de Cristo and the San Juan Mountains, the San Luis Valley is home to both the Great Sand Dunes and the headwaters of the Rio Grande. In fact, the dunes are made largely of sediments eroded from the San Juans by the nascent Rio Grande, which once deposited those sands into Lake Alamosa, a large lake filling the current valley. A drier climate caused the lake to disappear, leaving behind the sabkha, sandy wetlands that today still occupy parts of the San Luis Valley. Once fully dried, a sand sheet was left in the valley; southwestern winds built small parabolic dunes, which migrated northeast across the valley until they reached the foot of the Sangre de Cristo Range. Here, winds pouring out of Mosca and Medano Passes held the sand back, building the small parabolic dunes into great sand hills hundreds of feet high. The dunefield filled a small indentation in the Sangre de Cristos and became bound by Sand Creek and Medano Creek to the north and south.

The most straightforward route from High Dune to Star Dune- as I learned on my return- is to follow the outer dune crest, staying along the ridge of high dunes directly above Medano Creek and then ascending along Star Dune's south ridge. I was initially more adventurous, though, and chose to take an interior route, following the north ridge of High Dune out a little deeper into the dunes before turning west and making a cross-dunefield trek to Star Dune. While I generally tried to stick to ridges, I still had to drop into a few basins and climb back out; at times, this was extremely challenging due to the sinking sand.

Star Dune from afar
I noticed an interesting phenomenon as I hiked: the snow from the night before had been incorported into the sand dunes, with layers of snow deposited between layers of sand.

Snow and sand mixed
Another interesting feature: long dune features that resembled walls. These dunes had especially steep sides; I encountered a number of them on my dunefield traverse.

Wall-like dune
After trekking about 2 miles through the sand from High Dune, I arrived at the saddle marking the start of the east ridge of Star Dune. The ascent up this ridge was the toughest part of the hike: as I approached the top, the angle became ever steeper, so with each step the sliding sand carried my foot back to its starting point (quick note: while approaching via the south ridge is probably easier, you'll have to find some approach of ascending the steep east face of the dunes regardless of your path choice). A desparate push finally put me atop Star Dune, the tallest dune in North America.

Approaching Star Dune
On the slopes of Star Dune
A vast sweep of dunes filled the landscape between where I stood and the foot of the Sangre de Cristo Range. A little farther removed from that range, I could now see more of its peaks than I could at High Dune: Mount Kit Carson and the Crestone Needle were now visible. I could also see farther north to the head of the San Luis Valley and the snowy Sawatch Range that rose beyond that. The Sawatch is the highest range in the Rocky Mountains, holding Mounts Elbert, Massive, and Harvard, the three tallest peaks in all of the Rockies. The fourth tallest, Blanca Peak, is in the Sangre de Cristo Range and rises just to the south of the dunes; the tip of part of the mountain is visible from atop Star Dune, sandwiched between Mount California and Twin Peaks. To the west, the dunes died down until flattening out into the sabhka and San Luis Valley.

The Sangre de Cristo rise over the dunes, as seen from Star Dune
I returned by following the outer dune crest, keeping Medano Creek in sight for the most part on my return to High Dune. After catching the dunefield in dramatic evening light, I made a quick descent to the trailhead to catch a beautiful sunset from near the entrance station.

Although this hike doesn't follow a standard trail, it's a wonderful routefinding adventure and a chance to explore one of the continent's most unique landscapes. Don't miss it.

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