From the town of Randle on highway 12, head south on FR23 for about 15 miles. Look for for FR21 forking off to the left and turn here. Drive for about 5 miles then turn right on FR56. After about 2.5 miles, turn right on FR5603. Go straight for 4 miles then turn right on FR2329. Now drive 4.5 miles to the Killen Creek Trailhead (#113) at 4,600 feet.
Hike 3.1 miles up the Killen Creek Trail until you encounter the Pacific Crest Trail at approximately 6,100 feet. Turn left heading NNW and hike 1 mile, then turn right on High Camp Trail. Hike up to 7,000 feet and establish basecamp. You can also set your camp closer to the ridge if you like, but this would require more hauling with a full overnight pack.
On summit day, traverse accross the snow slopes below the Adams Glacier. Do not go higher than 8,000 feet, you will have to deal with crevasses. Find a spot to gain the main ridgeline south of the Adams Glacier. We found a good location at 7,600 feet.
The route basically ascends the rigeline all the way to the Pinnacle. Depending on snowpack conditions, expect to climb sections of loose volcanic talus and a boulder field. Try to stay in the 30 degree snow fingers on either side of the spine of the ridge. The lower part of the route is quite mellow, 30 degree snow and possibly some rock. At about 10,000 feet the route steepens to about 40 degrees. There is an enourmous rock outcropping at about 10,500 feet that forces you off the ridgeline. From here you have 2 choices:
1. North - Traverse a 50 foot long section on the snow slope of the North Face of the Northwest Ridge route (40 degrees). Now climb 40 degree snow in a C shape avoiding the steep headwall near the Northwest Ridge. After that, regain the 25 - 35 degree snow slopes above the ridge. This is easier than #2.
2. South - Traverse a 200 foot long section of the Pinnacle Headwall at a slope of 45 degrees. Now zig zag your way amoung smaller rock outcroppings until you can regain the snow slopes above the Northwest Ridge. There is a technical step about 4 feet high that must be defeated if you go this way.
Climb the final snow slopes to the Pinnacle Structure at just over 12,000 feet. From here you will have to descend into the crater then head back up the obtain the true summit at 12,276 feet.
A confident team with good downclimbing technique can easily decend this route. The North Ridge route is another option. Expect lots of downclimbing on loose volcanic choss over there.
Groups of good basic skill: Crampons, Ice Axe, Helmet
Beginners Add: Rope, Harness, Pickets, Runners & Biners, Belay Device
Do not bring glacier gear, there is no need.
If you want to read a report about the trip, it is located here.