Chasm Lake - 8.4 Miles Round-Trip

Chasm Lake is located 4.2 miles from the Longs Peak Trailhead in Rocky Mountain National Park. It fills a deep cirque carved from the base of Mt Meeker (13,911'), Longs Peak (14,259') and Mount Lady Washington (13,281'). Longs Peak's iconic 'Diamond' rises 2456' above this striking alpine lake. Visitors will enjoy miles of open tundra and sensational views on the hike to Chasm Lake:

Trail Map | Photo Gallery

The trail climbs steadily from the Longs Peak Ranger Station through lodgepole, spruce and fir. Alpine Brook, largely concealed by timber, is the only notable feature before crossing the top of a long cascade at treeline (1.85 miles : 10,615'), where the forest is quickly reduced to bands of krummholz.

Krummholz - a German word meaning twisted wood - describes the stunted, irregular growth patterns of trees in the ecological transition zone between subalpine forests and alpine tundra.

Poor soil, thin air and extreme weather limit growth at these elevations. Still, the tundra's nutrient-rich grasses, plants, and lichens support marmot, elk, bighorn sheep and mountain goat. 

The trail bends toward the Longs Peak diamond from the Battle Mountain Backcountry Campsite spur (2.45 miles : 10,956') to the Chasm Lake - East Longs Peak Trail split (3.25 miles : 11,518'). Stock is not permitted on the Chasm Lake Trail beyond this point.

The trail bears SW along the north wall of a deep gorge carved by Roaring Fork (Chasm's outlet) with views of Peacock Pool. It crests and drops across a steep slope to an alpine bench that spans the upper valley and separates upper and lower Columbine Falls (3.8 miles : 11,580').

This short segment is narrow, slanted and susceptible to slides. Traction devices are useful when snow-covered. The trail levels across this stream-crossed bench to the south side of the valley and Patrol Cabin (4.0 miles : 11,638'). Here the trail - more of a scrambling route chiseled from rock - climbs .2 miles to Chasm Lake (4.2 miles : 11,803').

Large boulders and uneven talus ring the lake, requiring some minor scrambling to the best viewpoints. An unimproved route circles Chasm Lake's talus-strewn north wall to the base of Mills Glacier, a shrinking remnant of the area's active glacial past.