From Timberline Lodge, navigate on the various climber routes towards Illumination Rock. Cross Illumination Saddle (c. 9000ft) and rope up. Head down across the Reid Glacier (can be heavily crevassed) and climb over Yoakum Ridge at either 8600ft (a climb and downclimb in itself) or scramble loose but low angle rock at 7400-7800ft. Head back up the ridge on the edge of the lower Sandy Glacier and then dig a bivy somewhere (probably well) below the bergschrund (appox 8000ft?). Get a nice alpine start for the climb the next day...
Head straight up the gut of the glacier with the upper hanging portion well on your left side. Cross the 'schrund as possible and then work up the obvious line of ascent as shown in climbit's route photos on this site. This is a really excellent portion of the climb! Great position, views, and remote feel.
The end can be a bit confusing. Entering the last AWESOME and steep bowl which finally opens up, there appears to be two (at least) distinct exits. One is a gully to the left (which leads to Cathedral Ridge); one is a line directly to what looks like "the top" sort of up and to the right. If you exit left, onto Cathedral Ridge, then turn right (up) on the ridge and follow it to the summit area. If you go straight for the steepest most direct exit, then you'll wind up exiting this small steep bowl onto a connecting ridge from Yoakum, at a location where it is difficult to tell which way is "up" in whiteout conditions. Turn LEFT (magnetic east / southeast) - not right, in order to hook up with Cathedral Ridge and on to the summit. Again, if in a whiteout, you reach the summit ridge area, turn again EAST (left). The summit register may or may not be visible depending on snow pack. The summit is the only area that is flat for any width - maybe 20m or more - and about 100m "long".
The south side descent route can be followed pretty much magnetic south from the west end of the summit platform. The Pearly gates will sort of compel and herd you to pass through the correct spot if you begin due magnetic south from that point. Magnetic south will also lead you into the Devil's Kitchen, so be careful there and skirt it to the west (where the true Hogsback route lies anyway).
This probably isnt a good idea for anyone's first alpine climb. I also wish I had climbed the South Side Route prior to doing this but I have an aversion to standard routes up peaks. It might've saved me a forced bivy and my wife some serious worry if i had known where everything was on descent prior to going up! :-)
Harness, crampons, ice axe, 2-3 ice screws, 2-3 pickets, 2nd tool, glacier rope super dry, 'biners, tent or bivy sacks (we had to use our bivy sack for a forced camp on the summit in a blizzard), compass, map, know how to use compass and map, shovel, food, stove, clothing systems, etc. etc. etc. Everything was encased in ice the last 20 hours of our little stay, so i like to use wire gate 'biners to avoid (minimize) freezing up and make sure your water bottle(s) are insulated.
Remember - this ain't a walk in the park to get to the route. It's serious up and down across 3 glaciers and 2 ridges (one very nasty) to get there. SO pack and plan accordingly. Retreat is a bitch.
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