Great Sand Dunes National Park: Mosca Pass Trail

On the afternoon of Tuesday, August 24, we continued exploring the parts of Great Sand Dunes National Park and Preserve that were not actually the dunes proper. We’d decided to save them for the following morning, when temperatures would be cooler. We toyed with the idea of driving to a trailhead on the other (eastern) side of the Sangre de Cristo Range to hike to a couple of alpine lakes high in the range, but the drive was almost two and a half hours.

So instead we opted for Mosca Pass Trail, which leads from near the Visitor Center complex up into the Sangre de Cristos to a low pass between the San Luis Valley and the Wet Mountains Valley. The hike was 3.5 miles to the crest of the pass, then 3.5 miles back to the trailhead. The Falcon Guide rated it Easy. We figured it would be a nice end to a day of hiking around the foothills zone between the dunefield and the mountains.

We were wrong.

Carbonate Mountain

From the Visitor Center, a short path led through juniper and piñon up to and across the road.

This part of the Park had burned some years before, and there was still signage warning of falling trees.

The short path ended at the triple trailhead for Mosca Pass Trail, Montville Nature Trail, and Wellington Ditch Trail, the route we’d taken from the campground. At the trailhead, there were little binders for interpreting Montville Nature Trail. Usually, we enjoy these, and Sean delights in declaiming the information. But on this late August afternoon, the mosquitos from Mosca Creek were intense. So we returned the binder to its alcove after taking some photos of its information. Then we continued on our way up Mosca Pass Trail.

The trail crossed a little bridge over Mosca Creek and then started up to the pass, keeping to the north (left) side of the creek. The area immediately adjacent to the creek was heavily wooded with Quaking Aspen and Douglas Fir, contrasting with the juniper and piñon of the more exposed and arid foothills we’d been hiking through all morning.

Douglas Fir

Shelf Mushroom

Douglas Fir

Douglas Fir

Douglas Fir

Plateau Fence Lizard

The slopes of the canyon, though, were sunny, particularly the south-facing slope that the trail traversed.

After an initial half-mile or so when the trail was in the shade near the creek, for much of the first couple miles of the hike, the trail was exposed and insistently uphill. It was fairly rough going, particularly for me. We were at an elevation over 8,000 feet—the Visitor Center is at 8,175 feet—so that obviously didn’t help. But the trail itself wasn’t particularly easy either.

Red Osier Dogwood

We crossed out of the National Park and into the National Preserve, a usage distinction pioneered in the system during the Alaska National Interest Lands Conservation Act of 1980, which created National Preserve designations for areas where traditional foodway activities like hunting and gathering would be allowed. This also marked the boundary of the federally designated wilderness area.

Rubber Rabbitbrush

Up we went as the canyon grew steeper above the creek.

Wax Currant and Starvation Prickly Pear

The area gave us a good look at three classic micro-climates/ecosystems of the Mountain West: arid piñon-juniper scrub on the south-facing slope, conifers on the more heavily wooded ridges and north-facing slope, and mixed coniferous and deciduous thicket in the riparian zone below along the creek.

Tailed Copper Butterfly on Rubber Rabbitbrush

Hoary Aster

Hairy Goldenaster

Image: Sean M. Santos

Black Bear scat

Scarlet Gilia

Quaking Aspen

About halfway up, the trail got a little less steep, as did the canyon walls. Here it passed through a broader riparian area along Mosca Creek.

Quaking Aspen


Then the canyon broadened considerably, and the trail passed through late summer meadows.

As the trail reached the pass, the climb became more difficult, not because of steepness, but because of altitude.

Ponderosa Pine

Quaking Aspen

We reached the pass. We had hiked four miles from the Visitor Center and risen 1,562 feet (to 9,737 feet above sea level) in just about two hours, fifteen minutes. Not bad, considering the altitude. But I do take issue with the Falcon Guide, Hiking Colorado’s Sangre de Cristos and Great Sand Dunes by Jason Moore, revised by Lee Hart. The guide describes the hike as easy, which was our ultimate deciding factor in tackling it that afternoon. The hike was not easy, particularly considering the elevation. The hike description was not accurate either. It reads, “Views of the dunes and the San Luis Valley to the west become more and more impressive as you approach the pass.” This is false. The dunefield and valley are only visible for a brief period about one-third of the way up the trail. Neither the San Luis Valley nor the Wet Mountain Valley is visible from Mosca Pass.

We passed through a fence and entered San Isabel National Forest. We continued up the Forest Service Road to see if the views got any better at the physical pass, maybe fifty yards further along.

They didn’t. We got the merest glimpse of the Wet Mountains to the east. The San Luis Valley was not visible at all, despite the guide’s description.

Well. Time to head back down.

In the moment, I was hot, tired, and cranky. And most of all disappointed. In retrospect, writing this over three months later, I’m glad we did the hike. Reframed in the guide as less a chance for views and more a chance to get up into the Sangre de Cristos to see some of the ecosystems of this magnificent range, I’d still have wanted to do it. And with a more accurate description in terms of strenuousness, Sean and I would still have hiked it, but we may have saved it for the morning, when we were more fresh. I guess the moral is that not all hiking guides—even those published by a generally trustworthy house like Falcon—are at the same level of accuracy.



The hike down went swiftly.

Hoary Aster and Showy Goldeneye

Ponderosa Pines

Over halfway back down, we got our views. Not unimpressive, certainly, but also not as described in the hiking guide.

We stopped in the shade to eat an apple before the final leg of the trail and chatted with a couple of hikers making their way up. We let them know that the views they were seeing now were the best they’d see of the valley.

Back down, we turned off from Mosca Pass Trail north onto Wellington Ditch Trail for the hike across the foothills back to the campground.

You really could just sit for an entire day just watching the light and shadow move over the dunefield.

Mount Herard

The hike back to the campground was level trending to gradually downhill, but it was hot, and we were definitely done.

Mule Deer Tracks

As we walked back into the campground, we made a quick stop at the camp store for Gatorades. Back at our campsite, I checked our stats: we’d done 12.7 miles, a really big day, particularly at elevations ranging from 8,100 to 9,700 feet above sea level.

We took turns using the car to charge our phones and access wifi. I went over the campground store to get a bit more firewood and some ice cream sandwiches. And I chatted with Kimberly, the proprietor.

The shadows grew longer across the dunes as we figured out our plan for the following day. We’d hike into the dunes in the morning, and then in the afternoon we’d check out a hot spring place up near the north end of the valley.

Piñon Pine

We built our evening’s fire and wiped down our gear and got set for the morning.

Mule Deer

The family that had arrived at the campsite across from ours got very excited about the group of Mule Deer that passed through camp. Ephemeral Garden Creek cuts through the campground immediately adjacent to our site. The deer were using its shallow ravine to move through.

Mule Deer

Mule Deer

I poured myself a local gin mixed with a blackberry sage kombucha while we prepared our dehydrated chicken and rice supper. We dressed it up with parm crisps for crunch and flavor.

After supper, we wrote postcards by the fire and then watched the stars come out, starting with Arcturus high above us.

Milky Way

Later on, the Milky Way was visible, and I messed around with trying to capture it. I like that the line in the photo above is the trail of a satellite moving in orbit around the planet.

Then it was time for reading in the tent before going to sleep.

2 thoughts on “Great Sand Dunes National Park: Mosca Pass Trail

  1. R Meek

    I greatly enjoyed your account of your trek up Mosca. I have not been there since about 1983, when I also hiked it without much prep. No guide, just saw it on the topo and thought I could do it with a light pack. That worked okay, but I was acclimated to 5500 then, so probably had an easier time of it than you at the top. Also, the upper areas were definitely not worth the trip, though I would not have been happy had I not tried. One thing you probably did NOT see, and that has piqued my curiosity ever since I was there, is that somewhere around half way up, off the trail a little ways in a stand of small pines, is the rusting body of a Model A Ford (or similar) that was abandoned there. The trees grew up through it. It must have been there since the 1930s or 40s, and it may have been a delivery vehicle (mail, government stuff, or just a farm car). I feel pretty sure it is still there, because it would have been tough to haul it out either direction. But where exactly it is/was, I cannot guess. I should have marked the map, but …duh. Anyway, it’s cemented Mosca in my mind as a neat little experience, and I agree that the best part are the brief views at the western end and the micro-climates you encounter all along. It was quite nice, and I really appreciate you posting all these pictures that re-energized my memories!


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