Day four of our Glacier NP backpacking trip: Many Glacier to Cosley Lake campground via the Ptarmigan Trail. 15.3 miles, 2,460' elevation gain, 2,490' elevation loss. The day started off clear, but the clouds rolled in quickly and it was drizzling by the time we reached Ptarmigan Falls, and continued on and off for the rest of the day. Fortunately the major rain only started after we finished dinner at Cosley Lake campground that night.