Intro

Sharkfin Tower may not be the tallest peak in Boston Basin—in fact, it’s significantly lower than Boston, Sahale, and Forbidden Peaks—but it’s an absolute blast to climb. With solid alpine granite, striking exposure, and a spectacular setting, this small crag tucked among North Cascades giants is both satisfying and scenic. Its summit offers unique mid-elevation views into the dramatic spires and ridges of Forbidden Peak, Boston Peak, Mount Buckner, Sahale Peak, and Johannesberg Mountain. Perched on the ridgeline between Forbidden and Boston, Sharkfin boasts high-quality rock and several routes. Fred Beckey's Cascade Alpine Guide lists numerous routes on all aspects, while more recent sources such as mountainproject and Selected Climbs in the North Cascades by Nelson and Potterfield list just a couple of routes: the Southeast Ridge (5.0) and the Southeast Face (5.10).

The first ascent of Sharkfin Tower was in 1947, via the Southeast Ridge. The Southeast Ridge is short and not especially technical, but it climbs solid rock in a breathtaking position. Views unfold continuously—Buckner, Boston, Sahale, and Johannesberg while climbing, with Forbidden, Eldorado, and a sea of other peaks revealed from the summit’s 360-degree perch.

My parents climbed Sharkfin via the 5.6 South Face back in August 1982. Originally, I had hoped to revisit the peak with my mom, planning to bring her up the 5.0 Southeast Ridge as part of an overnight in Boston Basin. But despite arriving at the Marblemount Ranger Station by 6:45 a.m., we couldn’t snag a permit. So we pivoted to two day hikes from Cascade Pass: On Friday, we hiked the Sahale Arm (I continued to tag the summit while my mom climbed to the base of the Sahale Glacier--click here to see trip report), and on Saturday, we headed into Boston Basin. There, I continued solo to climb Sharkfin Tower, while my mom relaxed in the stunning alpine scenery.

This page features a trip report and photo collection from my solo ascent of the Southeast Ridge (5.0) of Sharkfin Tower. I brought crampons for the snow and rock shoes for the ridge itself—thankfully, as my boots were soaked and muddy by the time I reached the rock, and climbing shoes made a big difference. Since moving to Colorado in 2019, I haven’t done much of the rugged, intricate North Cascades-style climbing, so I really enjoyed the route-finding, the mixed terrain, and the challenge of sticking to solid rock while minimizing hazards—all with the bonus of those stunning glaciated views. I found the second pitch—rated 5.0 like the others—to be notably exposed and more in line with 5.4, so I jokingly invented a new grade, "5.0+," and marked it that way on my topo.

After the climb, I rejoined my mom and we spent a couple of hours lounging beside a waterfall—reading, napping, and soaking up the alpine beauty. She declared Boston Basin the most beautiful place she’s ever been. I have to admit—it’s certainly a contender.

This page includes a photo smorgasbord from the day, along with a few vintage shots from my parents’ 1982 climb of Sharkfin Tower.

Photos

Approach - Hiking into Boston Basin

2nd, steep trail

Hike into Boston Basin. ~3.2 miles with ~2,500 ft of gain to the lower camp.

Approach - Snow, Approach Gully

moderate snow + 3rd/4th

From upper Boston Basin, ascend to the western edge of the Quien Sabe Glacier. From directly below Sharkfin Tower, ascend a gully*--snow in early season, scree by summer--through the steep rock band leading to a snow patch at the base of the tower. Climb a short gully to a notch at the base of the Southeast Ridge.

*Be sure to carefully identify the correct approach gully when climbing Sharkfin Tower. In a tragic 2005 incident, a six-person team mistakenly entered a similar but incorrect gully, leading to a complex traverse, rockfall injury, and ultimately a rappel accident that resulted in three fatalities and one serious injury. Misidentifying terrain can have devastating consequences—even for experienced climbers. AAC analysis of accident.

Pitch 1

5.0

From the notch below the southeast ridge, skirt the ridge to climber's right on large blocks, then follow a dihedral up a couple moves to the ridge and a belay.

Pitch 2

5.0+

Follow solid rock on the ridge proper with good gear. You can also climb a steep weakness feature just to the left, which may feel slightly less exposed.

I give this pitch a + (yep, 5.0+ is now a grade) because with the exposure it felt more like 5.4 to me.

Pitch 3

5.0

Scramble at or slightly right of the ridge to the summit.

Top

Woo hoo! What a view!

Descent - to Boston Basin

Scramble and/or Rappels

I downclimbed the way I came. There are several tat+rap ring anchors you pass on the way up, so you could rappel the route. The raps are over blocky/loose terrain, so rapping the route is not necessarily without danger or problems.