From the southeast side of the road that loops around the Dailey Prairie find the trail which branches from the main loop at about 48.722 degrees north, 122.030 degrees west; elevation 3240ft. This trail leads to the west ridge. Ascend the trail through the old growth firs until reaching the ridge crest. Follow the ridge to the summit.
The West Ridge of North Twin Sister is a wonderful scramble on superb rock. Follow the ridge crest whenever possible. In places where the ridge crest is obviously more difficult to reach than it is to traverse to the right, traverse. There are several places along the route where traversing a bit to the right and then climbing back to the ridge crest is the easiest way to travel. Most of the route is class three. There are a few class four sections and the climbing gets steeper as the ridge gains altitude. The quality of the rock, however, makes even the smallest handhold or foothold seem like a ledge. When climbing this ridge, one gets the feeling that there's no place where a good handhold or foothold don't exist. There is a wonderful route description which I won't plagiarize here in Fred Beckey's Cascade Alpine Guide, Volume 3. Read it.
Bring an ice axe prior to July as you will need it in the snow before you get to the ridge. Also, bring one if you plan to descend the north route, which is the quickest way down the mountian.
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