Mount Thompson: West Ridge

Alpine Lakes Wilderness, Washington

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Mount Thompson: West Ridge


  • The talus fields and forest along the trail are lush with flowers and berries.- Mount Thompson: West Ridge
  • Most of the approach follows the Pacific Crest Trail.- Mount Thompson: West Ridge
  • Mount Thomson (6,554') peeks up above a mountain ridge near Ridge Lake.- Mount Thompson: West Ridge
  • The cloud-filled basin on the other side of Bumblebee Pass.- Mount Thompson: West Ridge
  • Scrambling up the talus to the west ridge of Mount Thomson, which is somewhere up in the clouds.- Mount Thompson: West Ridge
  • Following the slab traverse on Mount Thomson's west ridge.- Mount Thompson: West Ridge
  • From the summit, there would be beautiful views on a clear day. Sometimes, this is all you get.- Mount Thompson: West Ridge
  • The Kendall Katwalk exposes hikers to a lot of air on the approach hike.- Mount Thompson: West Ridge
  • Red Mountain as seen from the PCT.- Mount Thompson: West Ridge
  • Mount Thomson's west ridge forms dramatic bumps and spires just west of the climbing route.- Mount Thompson: West Ridge
  • The first climbing pitch ends just above these trees.- Mount Thompson: West Ridge
  • The west ridge route is dirty, ledgy, and dotted with shrubs all the way up.- Mount Thompson: West Ridge
  • A view back at the false summit and scramble route down to the col.- Mount Thompson: West Ridge
  • On the way down, the climber's route follows the east ridge down into the basin south of Mount Thomson.- Mount Thompson: West Ridge
  • - Mount Thompson: West Ridge
Overview + Weather
Remote feeling route. Adventure climbing.
Long approach.
Alpine Lakes Wilderness, WA
Pets allowed: 
Recommended Equipment:
Harness / rope / anchors, Additional ice tools
Alpine climbing NCCS rating: 
Grade IV
Net Elevation Gain: 
3,600.00 ft (1,097.28 m)
Parking Pass: 
NW Forest Pass
Preferable Season(s):
Total Distance: 
16.00 mi (25.75 km)
Trailhead Elevation: 
2,955.00 ft (900.68 m)
Current Local Weather:
Adventure Description

Adventure Description

Pro Contributor

For the aspiring mountaineer, Mount Thomson provides a convenient introduction to alpine climbing. Its east ridge is mostly a walk-up with a short fourth-class section at the very end. Its west ridge provides a bit more of a challenge with five or so pitches of low fifth-class climbing. While many climbers bemoan the "long" approach, it is easy. Several miles of walking on the well-graded and maintained Pacific Crest Trail is all you need to get there.

A short but steep climber's path leaves the PCT just as it traverses above Alaska Lake. This path ascends to Bumblebee Pass, where you'll get the first good views of the mountain if the weather is good. Crossing a rock-strewn alpine basin to the talus on the other side puts you face to face with Mount Thomson's distinct profile. The technical climbing begins at a small notch just before the terrain gets vertical. 

The first two pitches are meandering and somewhat vertical, ending at the bottom of a broad slab. After the slab, there is a bit more vertical climbing to the false summit. A dirty trail leads down from the false summit to a belay notch, where the final pitch of climbing begins. A few quick moves lead to the true summit.

While the climbing is not technically demanding, you'll encounter a great deal of exposure, some loose and dirty spots, and some route finding challenges. Bring a light rack of cams sized to 3 inches in addition to nuts and plenty of slings to protect the climbing. Beware of rope drag. 

The descent route follows the east ridge. Two easy rappels and lots of hiking will bring you back to the basin beneath the south face of Mount Thomson.

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(20 within a 30 mile radius)

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(117 within a 30 mile radius)

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