I followed the water, which sent me up the south branch, where the canyon splits.
I subsequently found myself negotiating some rather difficult waterfall and cascade obstacles. At least the beautiful scenery would provide a lovely graveyard site if I fell.
At some point I was above the water and scrambling up the steep, loose headwall.
The wall was so steep with no real holds that I had to turn my palms inward and brace them against the sides of narrow runoff channels in order to propel myself upward at a radical angle. At one point I slipped and fell about fifteen or twenty feet before catching one of a few stable rocks. I kept ascending in a sketchy manner until my turnaround alarm went off.
So I turned around, perhaps a few hundred feet from the ridge. I slid down the wall on my butt, tearing up the seat of my pants.
Downclimbing the waterfalls proved scary, but I managed to not fall. On a couple of them I used some rather unpleasant bypasses, but the other ones did not have obvious bypasses, and I was probably doing Class 4 or 5 moves with not-that-solid and tiny holds.
It gets really maze-like in the upper reaches of Grizzly Gulch and navigation was also an issue.