On July 10 2004 Wes, Ed and I headed up the Centennial Ridge trail with Mount Collembola, not Mount Allan, being our objective. It was a beautiful morning and the long approach didn't seem very long at all and soon we came on an obvious trail snaking up to the left. This trail is before the CR trail actually breaks treeline and we foolishly second-guessed and kept going on CR for about 5 minutes till we got to a steep clearing and then headed up it to intersect with the trail (just take the trail!).
If you want to keep the scramble fairly basic stick to the ridge and cut around any cliff bands to the right. We decided to keep things interesting and headed around the mountain to the left and ended up traversing some steep (but fun) terrain to gain the top ridge.
Once on top of the ridge you have excellent views of the CR trail and you also realize that the summit is a ways away yet. It isn't as far as it looks and the ridge walk is so nice you won't care. It looks almost impossible to climb up to the left of the cliff band protecting the summit but it's really not that bad. We traversed over to the left and then went straight up through some 'greener' areas where the rock was a bit more solid. Rockfall is a real concern on this trip so either wear a helmet or go with a small group. (Both would be best!)
It was pretty windy on the peak so we didn't stay long. We were VERY tempted to head up to Mt. Allan and back down CR but resisted the urge and instead we spent a very leisure 1.5 hours making our way down the Jubilee Lakes valley. From the summit just continue to the col between the summit and the next cliff band and then head down scree to your right. Flower were out by the thousands and there was no wind. We witnessed a pretty big rock slide coming down from Mt. Allan - probably released by snow melt. We also saw about 20 sheep.
The walk back to the car was very long but still rather pleasant. I loved this trip and some day when I'm bored, I'll come back and do the circuit to Mt. Allan and back down CR from Collembola.
First look at Mt. Collembola's lower slopes and first false summit through the trees.