Looks like AWESOME rock, mostly 5.8 pitches with one 5.9 and one 5.7
Resources
- Steph Abegg
- Cascade Rock book
To camp
Backpack to Upper Cathedral Lake via Andrews Creek trail, it’s 19 miles with 5,511 feet gain.
Approach
About a 45 minute approach from the camp (far side of lake), only 1.3 miles with 470 feet gain.
Walk west from the lake on the trail over the pass and continue down past the one switchback until you spot the approach gully.
Looking back at camp from pitch 3, showing part of the approach…
A little bit after the switchback, you’ll start to see the gully where Southeast Buttress starts, to the left of The Monk. There’s not much of a trail going up to here, so choose your own path to the gully.
Pitch 1 – 5.8+
Climb a left-facing corner and wide crack in dark rock, belaying after 50 meters.
Pitch 1 of the SE Buttress of Cathedral Peak. 5.8+. 
Pitch 2 – 5.8
Chimney up, passing a huge chockstone to reach a thin corner on the right and a small stance.
Janet starting up the second pitch, which goes up past the chockstones and exits the chimney out right to a small stance. We climbed outside the chockstone, which felt hard until I stemmed across and was back making 5.8 moves. 
It would be possible to go behind the chockstone but it would be pretty grungy. I don’t think many climbers go that way. 
After going up some of the chimney, exit to the right on a ledge (rather than continuing further up), and then climb up a brief crack that leads to another widening chimney up to a ledge.
Looking up from the cross over ledge at the second half of P2.
As an alternative starting point, you can deviate and go to the right of the chockstone chimney (which takes you to the same cross over ledge).
Pitch 3 – 5.8
Continue up the small corner and crack to the right of the chimney, eventually passing a short wide crack and staying to the right of the chimney, eventually passing a short wide crack and staying to the right to reach a major ledge.
I think this is the start of (or somewhere on) Pitch 3 on the topo on the SE Buttress Cathedral Peak. It was our fourth pitch but our second and third pitches had been too short.
Pitch 4 – 5.8
Obvious cracks lead up and left into a left-facing corner and then up quartz dike, eventually gaining another flat ledge.
Quartz crystals at the end of Pitch 4 of the SE Buttress of Cathedral Peak.
Pitch 5
First walk across the ledge to the start of P5
Walk to the left side of the ledge and layback up a flake past blocks into a chimney feature which protects with small gear.
Pitch 5 starts with a rather burly layback up a flake. 
Pitch 5 ends with a chimney. From below it doesn’t look too enjoyable, but it is actually a really fun chimney and protects well with small gear on the left.
Pitch 6 – 5.7
Pitches 6 and 7 just follow blocks and corners to the base of the headwall above. Choose your own 5.7 adventure. We belayed at the tree on the ledge just left and up of center in the photo.
Blocky cracks and corners lead up and left toward the obvious headwall for two pitches, numerous possible belay ledges.
Pitch 7 – 5.7
Looking up Pitch 7 of the SE Buttress of Cathedral Peak. Blocky 5.7 cracks to the base of the headwall. There are lots of options.
Pitch 8 – 5.9+
The headwall has mostly hand-sized cracks and pitons for the first half, leading to a small belay stance, and a stellar finger crack lies just-right of the looming offwidth on the upper half. These two can be lead as a single 55m pitch.
Some cruxy thin moves at the start (can protect with small cams) and then eases up as it enters some hand cracks.
Janet starting up Pitch 8 of the SE Buttress of Cathedral Peak. This has a 5.9+ start to hand cracks above. The first of the two crux headwall pitches.
if the 5.9+/5.10 pitch on the headwall gives you pause, know that the “5.6 chimney” to the right (on the topo in an earlier edition of Beckey) is a natural line that climbs well and drops you at a big ledge at the base of the final pitch. We were not in a .9+ mood after 8 pitches, but if you are, the headwall is clean and proud.
Cascade Climbers
Starting the 5.6 headwall bypass 
Final moves to 4th class ground on pitch 9
Pitch 9 – 5.9+
From the top of Pitch 8, go right past a looming offwidth (shown in this photo) and to a finger crack about 4 feet to the right of the offwidth. The original route climbed the offwidth, but this is now usually skipped in favor of the finger crack. I actually enjoy offwidths but I would have wanted a #5 and maybe an extra #4 to lead it comfortably.
The offwidth option for Pitch 9 of the SE Buttress of Cathedral Peak. We chose the 5.10a fingercrack option. You would want at least a couple of #4’s and a #5 for the offwidth…. 
Looking down at the fingercrack. I sewed it up with gear. We felt the 5.10a grade given in our topo was fair. The hand traverse left at the top of the pitch also felt tricky. Excellent climbing on this pitch.
Pitch 10 – 5.8
An excellent final hand crack, broken into 2 parts by a ledge, leads to Cathedral’s summit.
The route finishes with a hand crack, broken into two parts by a ledge.
The handcrack got a bit wide near the top of the pitch. We were happy to have the #4 for the exit move from the handcrack, especially with the ledge below. Interestingly, the #4 had been really nice to have for both the first and last piece of the route. We placed it elsewhere on occasion although it was not really needed anywhere else. Other climbs in the are (such as on Amphitheater) require a #4, so if you have it with you already, you may as well bring it on the SE Buttress.
Topping out on the SE Buttress of Cathedarl Peak. We found the #4 to be useful to protect the final move. Irnoically, it had also been useful to protect the first move of the route. We were glad we had it.
Summit
Descent
Except for one section, the descent is an easy scramble to the West and then SW back to Upper Cathedral Lake. The crux of the descent is the section pictured in the photo, which the guidebook mentions you must hop across. We bypassed the hop by downcliming the exposed nose and easily stepping across. The downclimb is pretty easy (if dry!) but it is no-fall terrain.
Steph
The descent from Cathedral is towards the southwest. Except for a jump across a gap, it is Class 2/3. In this photo, Janet is downcliming to avoid jumping across the gap. 
Once off the summit area of Cathedral it is an easy hike down scree slopes to Upper Cathedral Lake. It took us about 45 minutes from summit to camp.
Steph
The mellow slopes leading down from Cathedral Peak towards Upper Cathedral Lake. ~45 minutes from summit to camp. Amphitheater Mountain in distance.
Plans
Cathedral Peak
Drive is 4:30 hours long Hike in should be less than 8 hours (a friend not in great shape did it in 7) Road conditions: Paved all the way to Andrews Creek trailhead Sunrise 6:15 AM, sunset 7:50 PM Thursday 8:00 PM leave home (after Bazar) 12:30 AM at trailhead, sleep Friday 8:30 AM wake…