The route mapped here approaches via the Pole Creek Trail and Camp Lake Trail. The same approach can be used for Middle Sister, so some climbers will turn this into a multi-day expedition and climb both peaks from a basecamp in the middle.

After departing from the approach trail, the climb begins in earnest. The route mapped here gains a spine and follows it all the way to the summit ridge.

Once on the summit ridge, the technicality ratchets up significantly. “In summer conditions, the traverse to the Bowling Alley, the final summit pitch up a loose, steep gulley, is on a narrow, crumbly, loose rock ledge and the Bowling Alley is Class 4 junk,” writes Brian Jenkins on SummitPost.org.

The final section to the summit mapped here traverses around the west side of the summit, makes a push to a saddle, then finishes the ascent from the north. However, note that conditions on the mountain can and do change, and route finding or an alternative approach may be required.

Sources: PeakBagger.com SummitPost.org