10 miles and 4,500-ft
Starting at the Pitkin Lake TH at 8,500-ft, locate the trail and follow it 2.34 miles to the first set of waterfalls at 9,920-ft. The first half mile is relentlessly steep. “Outpost Peak’s” rugged east slopes will be on your left and you can also make out the grassy, steep slopes of “Mount Solitude” up to the right. Continue on good trail another mile to the second set of waterfalls at 10,470-ft. Above the waterfall, you get your first good view of “East Partner Peak,” it is shaped like a pyramid. Hike another half mile past the second falls and locate some nice campsites in a flat marshy area riddled with trees. From here it’s about another half mile to Pitkin Lake. However, your turn off for the South Ridge Route is before the lake, see TOPO.
After 3.8 miles at an elevation of 11,000-ft you will officially be above tree line and “East Partner’s” defined south ridge will be looming directly above. However, before you get to the ridge the steep grass covered slope below it must be negotiated. From here to the summit is only 1 mile, but you must cover 2000-ft. This route is relentlessly steep.
Leave the main trail and begin your 1,300-ft hike until the slope begins to turn into a ridge at 12,300-ft. At this point the views really open up and East Partner’s” rugged southwest face will either impress you or intimidate you. Gain the crest of the south ridge and begin a slow, but fun scramble. The rock here is mostly solid and the climbing is class 3 with a few easy class 4 moves. At about 12,500-ft the rocky ridge quickly becomes a grassy ridge again, which makes for easy hiking before the ridge suddenly jumps up to the daunting summit pyramid.
The summit pyramid consists of deep inset couloirs that break up huge sweeping, steep slabs of granite. If one were to stay directly on the south ridge, I would imagine the climb up this section of the summit pyramid would be exposed class 4 and 5 climbing. However, the safest route from 12,500-ft involves leaving the ridge crest and traversing the steep east face until you locate easier climbing ground towards “East Partner’s” northeast ridge. The northeast ridge is the main spine of the Gore Range that connects to Peak W.
After traversing under the super steep summit pyramid, locate the weakness in the cliffs above. The route to the summit is more like an extremely steep rock face. Climb this face to the summit. The climbing here is steep, semi-loose class 3, with minimal exposure. Be aware of your ascent route when you reach the summit, it may be worth building a cairn so you can find the correct spot to drop off the summit for your descent.
Crampons, short rope and axe for an early season ascent (April/May/June), and I would wear a helmet, especially if someone is climbing above you.