Rainbow Mountain, just west of Whistler, is an excellent year round destination. Access is usually up 21 Mile Creek on a good trail that starts on Alta Lake Road and goes past Rainbow Lake.
The peak is best reached from the west, in winter or in summer. There are a variety of routes from this side, but all are easy scrambles. There's no real trail though, so you are on your own for routefinding once past Rainbow Lake. The climb to the summit is a long day trip in spring or summer, but usually takes 2 days mid winter.
21 Mile Creek is the drinking water supply for Whistler. Camping in the watershed is not permitted, although it is usually tolerated in the winter when fewer people visit the area. Good spots for summer camping are at Hanging Lake (official campground) or at Beverly Lake further north.
Rainbow Mountain can also be accessed from the Whistler Olympic Park in the Callaghan Valley via Hanging Lake - see the route description for Gin Peak. The final section between Rainbow Lake and the summit is the same for both start points.
The trailhead is located at the Whistler Cemetary on Alta Lake road in Whistler. If driving from Vancouver, the turnoff for Alta lake road is north of Function Junction and South of Whistler Creek on the left (west) side of the highway. Follow Alta Lake road for 6 km to a turnoff on the left for the Whistler cemetary. In winter, it's generally easiest to park at the cemetary and ski up the gated road rather than up the lowest part of the hiking trail. The hiking trail parking is about 200m further north on Alta Lake road. The road and trail join back together near the municipal water supply buildings, about 1km up.
Start skiing up the road from the cemetary to a couple of buildings by a map kiosk. Keep left here, following the directions for the Rainbow Madely Trail. There are two roads heading up 21 mile creek from this point; you want to be on the higher road. The road climbs steadily to about 1000m and then levels off. Past an outhouse the trail leaves the road on the left - this junction is easy to miss, especially in winter. The trail climbs gently back and forth through a logged area with lots of slide alder, soon reaching old growth forest. Once in the big trees, the trail is much easier to follow in winter.
At Xkm is a small clearing on the trail. This is the turn off for Mount Sproatt. To continue to Rainbow Lake, keep following the trail to a big log bridge and up a hill beyond. Eventually the trail reaches open meadows just before Gin and Tonic Creek. The markers become more difficult to follow, but the general route up the 21 mile creek valley is generally obvious. The deck of the bridge over Gin and Tonic creek is removed in the winter, so you will need to drop into the canyon, cross on a snow bridge and climb out the other side. This is generally done about 50-100m downstream from the suspension bridge. Beyond Gin and Tonic Creek, open meadows lead up to Rainbow Lake. The final climb to the lake is usually done in the forest on the north side of 21 mile creek.
Ascend Rainbow Mountain from the west to the small icefield south of the summit. The summit itself is guarded by cliffs, so cross a col east of the summit to the north glacier and approach the summit from there.
- Avalanche slopes on the west side of Rainbow Moutain. The CAC ATES rating for this trip is Challenging.