Boston Basin

Alpine Climbing

Boston Basin is one of the most popular backcountry zones for alpine climbing in North Cascades National Park and for good reason: the comparatively short approach paired with the high quality and densely stacked quantity of routes make it a perfect destination for climbers to continue to visit and explore year after year. The most iconic mountain in Boston Basin is Forbidden Peak, with multiple classic routes surrounding it on all sides. Most well known is the West Ridge of Forbidden Peak, listed as one of the 50 Classic Climbs of North America. But the other nearby routes offer similar quality of alpine climbing with a more private experience and the same high level of exposure and stunning views overlooking Moraine Lake and Eldorado Peak.

Torment - Forbidden Traverse (AD+, 5.6, V)

The ultimate Cascades ridge traverse, with over 1.5 miles of technical alpine climbing linking two iconic mountains in Boston Basin. This is an advanced alpine climb with two nights at an exposed bivy perch on-route. Though the grade is moderate, the route is defined by committing climbing over a long and exposed ridgeline, involving multiple rappels, down-climbing, traversing and steeper pitches of rock climbing. The Torment-Forbidden Traverse combines all the elements of summer alpine climbing in the North Cascades, it is a truly a classic alpine test-piece.

Day 1: South Ridge of Mount Torment

The normal approach to Boston Basin high camp and continue with cross-country travel to the Taboo Glacier below Mount Torment. The route begins by climbing the moderate South Ridge to the summit of Mt. Torment. We descend to a notch below the summit and sleep for the night on a small bivy ledge.

Day 2: Ridge Traverse

We begin the ridge traverse, with several rappels, steep snow traverses and sustained exposed rock climbing along the ridge crest. The climbing is moderate in grade, but committing and long making for a challenging day. We bivy for the night at the small perch at the notch below the start of the classic route, West Ridge of Forbidden Peak.

Day 3: West Ridge of Forbidden Peak and Descent

We leave our overnight kit at the bivy and climb the West Ridge unburdened by the heavier loads. We descend the same route and collect our bivy kit, rappelling the Cat Scratch Gully below and hike out to the trailhead.

North Ridge (AD, 5.6, IV), Forbidden Peak

Day 1: Approach

This first day begins with the same approach hike into Boston Basin and departing from just below High Camp towards the Quien Sabe glacier. We ascend a small rock step to Sharkfin Col and make 2 rappels down the remote and heavily crevassed Boston Glacier. Traverse the glacier to a small perch at the toe of the North Ridge of Forbidden Peak where we bivy for the night.

Distance: 5.5 miles
Elevation gain: 5,500 feet
Total time: 10 hours

Day 2: Summit

We climb the entirety of the North Ridge, following sustained and exposed moderate rock climbing to a final headwall guarding the summit of Forbidden Peak. Descend the West Ridge with down-climbing and a few rappels. We spend the night at a fantastic exposed bivy ledge at the notch below the route.

Day 3: Rappel and hike out

We start the day with 5-6 rappels down Cat Scratch Gully from our bivy ledge. Descend the snow and rock slabs below Forbidden Peak and hike out to the trailhead.

Bonus routes in Boston Basin

It is possible to combine itineraries for more efficient use of time in Boston Basin and climb multiple big routes, listed above. There are also several shorter routes that may be combined with a hike-in or hike-out day for fast and motivated parties to maximize your time.

North Ridge (5.4, II) of Aiguille de I’M:

A small peak separating the basins below Forbidden Peak and Mt. Torment, defined predominately by low 5th class rock climbing along a spectacular knife-edge ridge. The quick approach and shorter climbing make this route a great addition to the approach or hike out day.

South Ridge (5.7, III) of Sharkfin Tower:

A short vertical cliff with two pitches of high quality Skagit Gneiss rock climbing immediately off the glacier followed by a steep snow slope guarding the start of the route. Once on the actual route, the South Ridge of Sharkfin Tower ascends a steep, prominent arête with huge exposure to a few short low 5th class steps along the ridge crest. The views of Boston and Forbidden Peak are phenomenal.

Quien Sabe Glacier, Sahale Peak:

This route follows the prominent Quien Sabe glacier winding around crevasses and getting steeper towards it’s culmination at the col below Boston Peak. The route follows a rocky and exposed 4th class ridge for several short pitches to a small perch on the summit. The views looking down the Sahale Arm towards Cascade Pass are unparalleled.