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  • Writer's pictureJosh Kurz

Hike to Quartz Lake!

Alpine lakes are the gems of the San Juan Mountains - aquamarine water and surrounded by jagged peaks and wildflower-filled fens.

They owe their finite existence to powerful glaciers that once scooped out deep depressions in the bedrock as they slowly crept from the high peaks to join the ice-filled valleys below. As the glaciers retreated, the deep bedrock depressions filled with meltwater. Over time they will fill with the constant supply of sediment that is eroded from the peaks above.

The Quartz Lake Trail is one of the best places to see evidence of our glacial past, but first, you have to gain 2100 feet on the Little Blanco Trail and pass through the keyhole, a narrow gap in Quartz Ridge with an elevation of 12,090 feet.

The Little Blanco Trail is in great shape and is currently lined with an amazing assortment of wildflowers some of which are taller than me. The dangerous snowfield just before the keyhole no longer covers the trail.

Once you pass through the keyhole, you'll be standing at the headwaters of the Blanco River whose deep valley unfolds beneath your feet.

Walk a narrow ledge and then gain a short rocky ridge and you may think you've been teleported to Ireland. Smooth, pink bedrock outcrops are intermixed with small ponds and green, spongy tundra.

This section of trail is the best location to see evidence of glacier scouring. Ice is not hard enough to grind down rock, but boulders frozen in the bottom of glaciers are! Rocks that are frozen in the bottom of glaciers slide across the bedrock and leave grooves called glacial striations and they also smooth and round the bedrock leaving glacial polish. Much of the glacial polish has weathered, but the bedrock is still rounded and fairly smooth.

Lastly, when glaciers melt, they drop the boulders that are frozen within them and these large conspicuous rocks are called glacial erratics.

While you're admiring the glacial scour, look and listen closely for ptarmigan, still mostly covered with white feathers to match the patchy snowfields. I also spooked some grouse (they spooked me).

This section of trail with best glacial evidence is short, but the views continue. The Continental Divide and Archuleta County's highest peak, Summit Peak, are covered with verdant tundra towards the northeast. Surprisingly, you will have to cross a small snowfield, which might linger until the snow flies again in September!

Shortly after the snowfield, you'll pass through a dark vesicular igneous rock formation and crest a small ridge. At that point, you will enter the Quartz Creek watershed, which is a tributary to the East Fork of the San Juan. Any water that you step over may literally float tubes on the San Juan River through Pagosa Springs the following day.

At this point, you may be able to catch glimpses of the lake below you to the north. You probably won't traverse this next section of trail without getting wet feet and losing the trail (especially on the way out). Pay attention to landmarks such as the ridge that you just passed over. The trail passes over large sections of bedrock just before the lake, but if you look closely you may see cairns marking the vague route.

As you drop steeply to the lake edge, you'll hear water trickling out of the lake and cascading over a nearby waterfall. As you're basking in the sun (because you got to the trailhead at the crack of dawn and the thunderstorms are only beginning to form), you'll see brook trout feeding on emerging insects. Unless you're spending the night, you'll need to beat the thunderstorms to the keyhole, which requires gaining back 600 vertical feet.

You'll want to make Quartz Lake a summer hiking destination especially during peak wildflower season. If you miss the wildflowers, then it will be berry season, but at least make sure you visit before the lake fills in with sediment. Otherwise, you'll have to wait till the next ice age for glaciers to scoop it out again. For more detailed trail information, visit


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