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Collier Glacier

The Largest and Most Accessible Glacier in the Three Sisters Wilderness

Glacier in Deschutes NF, Willamette NF, Three Sisters Wilderness, Cascade Range near Sisters, OR

Although it has shrunk to about half its former size, Collier Glacier is still impressive. It forms at 9000 feet on the ridge connecting the North and Middle Sisters, and follows a path to the northwest. In the early 1900s it reached as far as Collier Cone, almost two miles, and according to accounts the ice rode high on the southern side of the cinder cone. Today the glacial ice stretches for one mile. An impressive icefall stands above the sloping terminal ice sheet, which is split by crevasses.

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On Wikipedia

Collier Glacier is in the U.S. state of Oregon. The glacier is situated in the Cascade Range at an elevation generally above 8,000 feet (2,400 m). Collier Glacier is on the west slopes of North Sister, an extinct shield volcano. Since its last maximum extent during the Little Ice Age (1350–1850 A.D.) the glacier has retreated over a mile.

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On the lower glacier, below the icefall, the slope is gentle enough for walking although crampons or micro-spikes are necessary. (Of course, unless it is late in the summer and the blue ice is exposed, snow-bridged crevasses are a danger. It’s safest to admire the glacial formations from solid ground.)

There are no trails leading to the valley of Collier Glacier, and all approaches involve some hazards. A user trail leaves the Pacific Crest Trail just east of Oppie Dilldock Pass, and crosses the west-facing mouth of Collier Cone before climbing the southern wall of the cone. (Don’t confuse this trail with another nearby, which climbs to the cone’s northern rim.) An off-trail descent down loose rock from the cone into the valley is required. At some seasons the muddy melt-water lake which forms in the lower valley may be an obstacle. Another, longer route is to leave the Pacific Crest Trail just south of Minnie Scott Spring, and circle around the east side of Collier Cone. This takes the hiker across the spare, Mars-like cinder plains between the cone and the North Sister. The descent into the valley here also involves loose rock. Some of the rocky debris is underlain by old ice (see picture, below) and can be unstable. A further note of caution: avoid the steep moraines, like the gray 400-foot-high lateral moraine pictured below. Rockfall is frequent, and almost anything triggers an avalanche of boulders.

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Glacier