SE slope

Page Type
Washington, United States, North America
Route Type:
Spring, Summer, Fall
Time Required:
One to two days
Class 3
Rock Difficulty:
Class 3

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SE slope
Created On: Oct 26, 2006
Last Edited On: Oct 29, 2010

Approach route to Trap Pass

Tunnel Creek trail to PCT trail

Take the Tunnel Creek trail (trail # 1061) for 1.6 miles. The trail ends at Hope lake. From Hope Lake head south on the Pacific Crest Trail. You'll hike up switchbacks for about .5+ miles to a saddle and then it levels out a bit. Once you cross the ridge you start to traverse the slope on the south side. You come into a meadow and then the trail basically levels out and traverses for a couple of miles (with great views and meadows) till you start the switchbacks up to Trap Pass above Trap Lake.

TH at 3100', Hope Lake at 4400', Trap Pass around 5800'; 5.6 miles to Trap Pass on easy trail.
The ridge

Image taken and used with permission by Tazz.

Surprise Lake trail
This approach may be a mile shorter but it is an extra 800' or so gain. It also is in the trees for the entire hike. Take Surprise Creek trail (#1060) 4 miles to Surprise Lake. From Surprise Lake turn left on trail #1060.1 ascend many switchbacks to Trap Pass.

TH at 2400', 4.6 miles to Trap Pass.

Route Description

From Trap Pass head south on a well established climber's path that takes you along the ridge. The path is easy to follow. Ascend to around 6200' give or take. This is when you come into the first open meadow just below Slippery Slab Tower.

Image taken and used with permission by Tazz.
Slippery Slab Tower

Image taken and used with permission by Tazz.

From here, it'll be a traverse through meadows and over boulder and talus fields. (Fragile meadows! Please try to stay on trails or rock!) The main path dwindles into granite slab and boulders. You can lose and find a path all the way to Thunder Pass. From the base of Slippery Slab Tower, traverse your way around the ridge for about 1+ miles only gaining a couple hundred feet.

Next, you come to the ridge that you must cross to drop down to Thunder lakes. There are two saddles to choose from, both work equally well. We took the one just under Nimbus Peak on the right.

I came back out through the saddle on the left. You can just see the summit of Thunder Mountain from the saddle.
Upper Thunder Mountain Lake

Image taken and used with permission by Tazz.

After you drop down you will not see Thunder Mountain again until you climb up the ridge above Thunder Lake or traverse all the way around the ridge.

From the lake you have a choice to take the E-NE ridge proper or drop to an easy traverse to the SE slope. The ridge involves quite a gain to only lose it again. It also is a bit more sketchy (class 3+) dropping down.
The ridge

Image taken and used with permission by Tazz.

It is rotten and hard to find the route in places along the ridge.

I would recommend the SE slope traverse, as it is faster and easier. From the south corner of the lake drop down a bit to a large bench and follow it to a gully. Drop down into the gully and find a small shelf that takes you around a small ridge.
The traverse

Image taken and used with permission by Tazz.

Stay on a descending traverse until you see Thunder Mountain off to the right. Shoot for the small gully/saddle to the west of the summit block. Ascend several hundred feet up a steep heather slope. All class 2.
The traverse

Image taken and used with permission by Tazz.

Once at the saddle, scramble left over some boulders or trees to the right and ascend. From here the summit block is solid class 3 to a tiny summit.
The last push

Image taken and used with permission by Tazz. Descend the same way.

Essential Gear

A helmet suggested in the gully, particularly if you're in a party of two or more. The talus below the summit came from somewhere!
Ice axe and crampons in early season.

SE slope

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