At 2,426 meters, Frosty Mountain is the high point of EC Manning Park. It lies about 1 kilometer west of Frosty Mountain East (2,409 meters), a popular hike with a nice trail. Frosty Mountain can be reached from the Frosty Mountain East summit through a tough and exposed scramble. However, the preferred option in winter is a terrific outing that crosses two lakes, has a nice open bushwhack in a beautiful forest, and ends with a dramatic ridge traverse.
This adventure starts at the Lightning Lake boat launch. Cross Lightning Lake to where it narrows, 1.5 kilometers southwest of the parking area, and continue to the southernmost point of Lightning Lake after it widens again (another 1.5 kilometers). The lakes will be frozen and snow-covered in winter. If the lakes are not frozen or if you don’t trust the ice, the Lightning Lakes Chain Trail will take you to the same place over a slightly longer distance. Over these 4 kilometers of flat hiking there are nice views of some of the more remote mountains in western Manning Park.
From the end of Lightning Lake, which sits at about 1,250 meters of elevation, the grueling part of this outing begins. You will have to bushwhack to the southwest to reach tree line and the summit ridge. The bushwhack is steep, but it is open and has occasional flagging. You should bring a map and compass or have a GPS to avoid getting lost. The ascent to the ridge is roughly 2 kilometers and has about 800 meters of elevation gain. With a little luck you will find snowshoe or ski tracks, but come prepared to break trail and sweat a little!
The treeline is reached at around 2,100 meters of elevation, where a thin forest of larch trees allows some of the first views of the day’s objective. From this point navigation will be easy because all that remains is a rocky ridge traverse. Don’t take it lightly though: It’s over 300 meters of ascent on mostly exposed scree and rock. Because of the strong winds, this section is unlikely to be completely snow covered. Snowshoes or skis can be ditched at treeline and replaced by crampons and an ice ax.
The summit of Frosty Mountain is the obvious highpoint at the end of the ridge. It is located less than 2 kilometers north of the U.S. border and about 3 kilometers northwest of the Pacific Crest Trail's northern terminus. Beautiful summits such as Hozomeem, Freezeout, Castle Peak and Frosty East can be seen, as well as Flash Lake, Lightning Lake, and the northern part of Manning Park.
From the summit, retrace your steps to the parking lot. The descent will be much quicker because it is on steep snow and the path will now be broken.
Note: This outing could almost qualify as a snowshoe or microspikes adventure. The bushwhack portion is not especially hard, but it does require some route finding. Also, the summit ridge is a little exposed and has cornices, so it is important to choose the right path for the final ascent. Mountaineering equipment is definitely recommended.