Round-Trip Length: 11.1 miles
Start-End Elevation: 9,981′ – 12,577′
Elevation Change: +2,731’
Skill Level: Difficult
Trailhead Location: The Arapaho Glacier Trailhead starts at the Rainbow Lakes Trailhead. The trailhead is located 5 miles west of Highway 72 on Rainbow Lakes Road (a.k.a. County Road 116 – National Forest System Road 298). Rainbow Lakes Road is located 7.35 miles north of Nederland, CO. Turn west from Highway 72 on Rainbow Lakes Road and keep straight past the University of Colorado Mountain Research Station access road and Caribou 4WD turnoff, through the Rainbow Lakes Campground to the small parking area at the road’s terminus at the trailhead.
I had been wanting to hike this trail for a couple of years. A few weeks ago some friends and I attempted the hike from the north starting at the 4th of July Trailhead. However, the weather did not cooperate that day and we had to turn around a little over 3 miles into the hike as it was pouring rain. This time I started from the south side at the Rainbow Lakes trailhead. The trail takes you up above treeline with great views into the Boulder watershed including Silver, Island, and Goose lakes.
The start of the hike.
In a quarter of a mile, I took a right onto the Arapaho Glacier Trail.
Taking a left at this junction will take you to Rainbow Lakes. You can read about the Rainbow Lakes here here.
Shortly after the trail junction, I entered into the Indian Peaks Wilderness.
The first two miles of the Arapaho Glacier trail take you up through the trees on a fairly mellow trail. The trail then comes out of the trees into the open tundra. My first views looking back to the east and the sea of clouds I was to the west of and above.
I continued on up the tundra with views of the Indian Peaks.
Soon I got a great view of Silver Lake and Island Lake down below.
This series of Lakes (Silver, Island, and Goose lakes) are a part of the Boulder watershed and are off limits to the public. In 1929 the U.S. Congress deeded most of the land in the Silver Lake Watershed to the City of Boulder specifically for water supply purposes. The watershed contains 13 reservoirs and natural lakes that are fed by snowmelt and the melting of Arapahoe Glacier. This high-quality water supply was sufficient to meet all of Boulder’s water needs until the 1950s. Today about 40% of the city’s water supply is derived from the Boulder watershed basin. In order to protect water quality and to preserve the fragile alpine environment, the Boulder Watershed is closed to public access.
A view looking up the valley towards Goose and Triple Lakes.
Looking back to the southeast to Rainbow Lakes.
A look even further to the southeast at Barker Reservoir in Nederland.
A backpacker heading across the tundra.
A small tarn up to the northwest.
The trail continued up across the tundra, making large switchbacks. It was quite windy and cold up here but at least it was sunny. At 4.4 miles I reached the saddle where I could get views back to the south and west.
I continued on up past the saddle to the west and headed up. At 5.5 miles I finally decided to turn around. From what I could tell, I was almost to the point we had hiked up from the 4th of July Trailhead a few weeks earlier.
Heading back, I took in more views of the lakes. A look back down onto Island Lake.
A panoramic view of all of the lakes.
And, a shot of myself.
I continued on back down the trail. I was pretty tired by the time I reached the car. It had been a while since I had been on an 11-mile hike and add to that over 2,700′ of elevation gain, it was quite a workout for the day.
My route: