Page Type Page Type: Mountain/Rock
Location Lat/Lon: 39.65361°N / 106.18046°W
Additional Information County: Summit
Activities Activities: Mountaineering
Seasons Season: Summer
Additional Information Elevation: 13333 ft / 4064 m
Sign the Climber's Log


“East Thorn Peak” rises to 13,333 feet above sea level in Colorado’s Gore Range. It’s about half a mile east of “Mount Silverthorne,” the latter being an unofficial name for the 13,357-foot peak labeled with the Willow horizontal control monument on the USGS 7.5-minute quadrangle. Although “Mount Silverthorne” dominates the southern Gore Range in elevation and sheer mass, “East Thorn” presents a more striking appearance from the town of Silverthorne, and climbing it from any direction demands more skill.

The route described here is essentially that described in Dave Cooper’s excellent guidebook, Colorado Snow Climbs (CMC Press, Golden, CO, 2007). Starting in the Salmon Lake cirque northeast of the summit, the route ascends a north-facing snowfield to a saddle, then follows the rocky east ridge to the summit.

Getting There

The fastest approaches to the base of "East Thorn" start in Silverthorne, Colorado. An efficient Forest Service trail, shown as the Willow Lakes Trail on the 7.5-minute quadrangle, has a cut-off to Salmon Lake. There are several ways to reach the Willow Lakes Trail from Silverthorne. Theoretically, the shortest is the North Willow Creek Trail, which starts near the western terminus of Willowbrook Road in Silverthorne and roughly parallels North Willow Creek until it intersects the Gore Range Trail. If you use this route, brace yourself for three problems:

1. The route doesn’t appear on the topographic map.
2. There is no overnight parking at the Willowbrook Trailhead.
3. Many confusing, poorly marked trails crisscross this area.

For additional, curmudgeonly comments about problems 2 and 3, see “Red Tape” below.

You can always use the Mesa Cortina trailhead. It has free overnight parking and involves few confusing intersections. It requires about six additional up-and-down miles round trip, all of them through beetle-ravaged lodgepole forest.

Route Information

We climbed the east ridge in mid-June, after an unusually dry spring. Near the 11,800-foot contour line at the south edge of the Salmon Lake cirque, we started ascending a snowfield about 700 vertical feet to a cairned saddle on the mountain’s east ridge. (There was a steeper, narrower snowfield on climber’s right. To us it looked like a funnel for loose rock.) Ascending the snowfield is straightforward, involving 40-degree snow with a relatively low risk of rockfall.

From the saddle, we turned west and scrambled on rock, with scattered grassy ledges, beginning climber’s left of the ridge crest. We stayed near the crest, on dry class 3 rock. It was often steep but never lacking in hand- and footholds. As with most seldom-climbed peaks, you’ll have to manage loose rock. There are two exposed traverses. On ascent, the first involves a narrow, sloping ledge with air on climber’s right. We belayed it with a rope. After the second airy, à cheval traverse, which we didn’t protect, we scrambled up a short, exposed step to the summit.

We descended by down-climbing the ascent route.

(As shown in the primary photo for this article, it appears possible to reach the cairned saddle from the south by scrambling up steep grass and scree from the Willow Lakes cirque.)

Red Tape

“East Thorn” stands in the heart of the Eagles Nest Wilderness. Federal wilderness restrictions apply.

The prohibition on overnight parking at Willowbrook trailhead is just the tip of an ugly iceberg: the city of Silverthorne allows no overnight parking on public streets or in public parking lots. After some investigation we circumvented this unfriendly restriction by asking a private proprietor — the Silver Inn on Route 9 — if we could park in their lot for a few nights. They didn’t charge, but we tipped. Then we dropped the packs at the trailhead, parked the car, and used the Summit Stage, a free bus, to ride back to the foot of Willowbrook Road, about a mile downhill from the trailhead.

Our solution to the irritating parking problem didn’t spare us from a second nuisance. The privately owned open space between Silverthorne and the National Forest boundary is laced with a maze of hiking trails, far too few of which possess markings that nonlocals can decipher. For example, there are at least two trails, neither meaningfully marked, that leave the Willowbrook trailhead. One trail roughly parallels North Willow Creek; the other roughly follows South Willow Creek. They run at nearly right angles to each other. A mistake costs about two miles. Even if you choose correctly, plan to puzzle over additional mystifying trail intersections, unadorned by signs, on the way in and out, whenever you’re not safely within the Eagles Nest Wilderness. It is an irony of modern mountaineering that route-finding is almost always easier in the wilderness.

You may be lucky enough to meet a sympathetic and informative local to help, but there are locals who exhibit neither trait.

That’s enough ranting. Once you overcome the trailhead hassles, East Thorn is a stellar scramble in one of Colorado’s truly gorgeous mountain ranges.


The Salmon Lake cirque is rocky and rugged, with a small number of one- or two-tent campsites near the main creek below timberline. The stunning Willow Lakes cirque has spacious meadows and many excellent campsites with abundant water.


On the snowfield we used ice axes, crampons, and helmets, all highly recommended. Because it faces north, the snow remains icy for several hours in the morning. We brought two 35-meter half-ropes (for a threesome), harnesses, BD stoppers 6 - 13, BD camalots 0.4 - 2, four alpine quickdraws, and a cordelette. We could have left every other piece behind. Bolder climbers can leave all rock gear at home. In dry weather, the scrambling portion of the climb had significant exposure, no moves harder than class 3 (requiring hands, feet, and balance), and no need to rappel.