ApproachBegin at the trailhead at Glacier Lodge and follow the North Fork of Big Pine Creek trail. Follow the drainage to the Big Pine Lakes. After you pass 3rd Lake, continue on to Sam Mack Meadow. On Sam Mack Meadow, do NOT follow the signed Glacier trail that goes to the left from Sam Mack Meadow, continue south to the end of the box canyon. Climb the wall at the head of the canyon to the crest of the current terminal moraine for the Palisade Glacier. I found the best option to go up the "steepish" gully on climber's right (portions covered with snow all year) and follow the weakness to the glacier. Camping spots and running water can be found along the way. I highly recommend going as far as possible (i.e. as close to the glacier as possible) to cut down on the approach time next day. Once you reach the end of the moraine, you will see Thunderbolt Peak in front of you. Descend from the moraine to the glacier below and to the right (norteast) side of Thunderbolt.
Route DescriptionThe Northeast couloir is the narrow couloir to the left of the wide North couloir that goes diagonally to the right and ends on the top of the Prow. The first section is a snow climb (early October 2005) that steepens as you get closer to the ice. Then two full pitches of water ice (40-45-50 (?) degrees) follow, followed by a short section of snow and then approx. 1 pitch of class 3-4 rock. Aim for the visible notch in the ridge. From the notch, continue up left to the main ridge. Follow the main ridge to the notch just left of Lighting Rod. This last section is quite long and can be exposed. Easier climbing can be found on the right side of the ridge. When we climbed this route in early October 2005, fresh snow covered the rocks, making what would otherwise be Class 3, a more difficult route (finding holds, postholing, etc.). Suggested descent via North Couloir.
This route is described as Route 7, NE Couloir, III 5.6 in "Climbing CA 14'ers" as a rock climb - you can apparently bypass the ice on the rock on either side (right side when looking up looked easier).