Great conditions for a late summer climb!
Starting out from the Mowich Lake trailhead, my brother and I were able to find the Knapsack Pass trail next to the ranger cabin with only a little difficulty. There was a blowdown right across the start of the trail, obscuring it. While it had been misting down at lower elevations, the trail was dry and in good shape. (We were told that wet conditions can be nasty on the Knapsack Pass trail.) As we gained elevation, the cloud deck lowered so we had sun and moderate temperatures most of the way up. I was pleased to find some avalanche lillies still in bloom on the west side of the pass. Some wild blueberries, too!
Beyond the pass and heading for the main Spray Park trail, there is a lot of independent routefinding to do, picking your way through the boulders. It's definitely easier to get to Spray Park via Knapsack than it would be to head back to Mowich the same way.
From the 6400 foot high point on the Spray Park trail, we found the path heading up towards Observation Rock. The path is clear up to a snowfield at about 6800 feet. Take the snowfield up to nearly 7000 feet, then go up over or around a rocky hill and you will find a sweet campsite with windbreak at the bottom of another snowfield. (Park regulations forbid building new windbreaks or clearing new backcountry campsites, but this one is already in place.) The campsite has a fantastic view towards Echo Rock, The Mountain, and Observation Rock, and a creek running off of the snowfield about 100 feet away. We had started our trip on a Friday just to increase our odds of landing a great spot like this one, perfect!
We set up camp and hung around in the evening, tromping up the little snowfield to take a look at the Flett Glacier and plan our route for the next day. Temps must have dropped to freezing overnight, because the creek had ice on it in the morning, and there were also ice crystals in the dirt in camp. We were glad we had our 15 degree bags!
Our goal for the trip was to climb Observation Rock on Saturday. The front slope of the Flett above camp looked a bit steep and icy to us, but we're just building our skills and it appeared that others went right up it. We elected to instead head cross-country to the west, crossing bounder fields and other arms of the Flett, to ascent to Ptarmigan Ridge. The western end of the Flett has a marvelous 30-foot wide ramp sloping easily up to the Ridge. More rocky travel followed, and we easily found our way up the back side of Observation, all the way to the top! Bluebird conditions, and 360 degree views including looking down on Echo Rock 500 feet lower. We took 2.5 hours from the campsite to the peak via this route.
After lunch on the rock we decided to head down on a somewhat more direct route toward camp, on the Flett along the edge of Echo Rock, down to the point where it became too icy and thin, where we hopped onto the red rocks and went cross-country back to camp to rest and enjoy the evening. 1.5 hours from the summit back to camp. That evening we finally met some other hikers; since leaving Mowich we hadn't met a single person for over 30 hours.
Sunday morning was clear and cool at altitude after another freezing night, and our hike back to Mowich Lake via the main Spray Park trail was a joy! It was sunny throughout Spray Park, the air was cool and just slightly moist, and many of the wildflowers were still in bloom. Best of all, there were no biting bugs that morning! We had such a good time that I'm already keen to go back!