Afternoon storm risk is the line that matters. Everything else is comfort. In summer, plan to be off the ridge before the build-up starts, not as it starts. Forecast for the summit point, adjusted for its elevation · data from Open-Meteo.
Colorado 13er · Southwest Ridge from Willow Basin
Overview
UN 13,350 rises above Willow Basin, north of the Maroon Bells. It is half red Elk Range rock and half pale granite, like Snowmass and Capitol. From Maroon Lake you follow trails over Willow Pass, across Willow Basin, and up to a pass on the East Snowmass Creek trail. From there it is about 700 feet up the southwest ridge.
It is Class 2+: small cliff bands low down on red dirt and rock, then a slog up broken white boulders. Staying just west of the crest is easiest.
The round trip is about 12 miles with about 5,000 feet of gain, including the climb back over Willow Pass. Mileage and gain are our estimates. UN 13,015 is a 20-minute side trip from the same pass.
Plan of the day
Start by
Catch the first shuttle, or be parked by 5:30 a.m. with a reservation.
Turnaround
Be at the pass above Willow Basin by 10:30 a.m.
Crux
Broken white boulders near the top, very slick when wet.
Route-finding
Moderate. Trail all the way to the pass. Then stay on the west side of the ridge, just below the crest.
From the roundabout on Highway 82 just west of Aspen, take Maroon Creek Road (County Road 13) south toward Aspen Highlands and Maroon Lake. About 4.7 miles in is the entrance station, where you pay a fee.
In summer the road is limited: you need a parking reservation, often made months ahead, or you ride the shuttle bus from the Aspen Highlands lot. Check the White River National Forest website for this year's rules before you go. There is no camping at Maroon Lake. Silver Bar, Silver Bell and Silver Queen campgrounds along the road are small, reservable and usually full.
Trail in the treesRidgeTalus and screeExposed to lightning
The line is elevation, the band underneath is the ground, and the numbered dots match the steps below. Mileage and elevations are approximate.
1
Maroon Lake trailhead 9,600' · 0 mi
Take the Crater Lake Trail (1975) along the lake. Don't get pulled onto the scenic loop around Maroon Lake. Overnight campers must register at the trailhead and carry a bear canister.
2
Crater Lake junction 10,080' · 1.8 mi
Near Crater Lake, turn right (west) on Trail 1978 toward Buckskin Pass. It climbs hard up Minnehaha Gulch.
3
Minnehaha Creek 11,060' · 3 mi
About 3 miles in, the trail crosses Minnehaha Creek. There have been good campsites on the ridge just before the crossing; check current camping rules.
4
Willow Pass junction 11,700' · 3.4 mi
Continue a little farther toward Buckskin Pass, then turn right (north) on the trail to Willow Pass.
5
Willow Pass 12,580' · 4.2 mi
Climb tundra, then red rock, to the pass.
6
Willow Basin 11,950' · 4.8 mi
Switchback down into Willow Basin, a huge tundra bowl dotted with red boulders and orange lichen. Just below 12,000 feet, before Willow Lake, take a trail heading west.
7
East Snowmass Pass 12,700' · 5.5 mi
Climb the side trail through white rubble to a pass between UN 13,350 and UN 13,015, marked by a post where the trail drops into East Snowmass Creek.
8
Red rock 13,000' · 5.8 mi
Head north up soft red dirt and rock on the west side of the ridge, working through a few small cliff bands.
9
Summit 13,350' · 6 mi
Higher up, switch to rubble of broken white rock and grind your way to the top. Views of Snowmass Mountain, Snowmass Lake and Capitol Peak.
Watch for: Slippery when wet.
Getting down
Return to the pass. Add UN 13,015, or head back across Willow Basin and over Willow Pass.
If things go wrong
The pass and its trail are close below.
3D flyover
No 3D flyover for this peak
Above the pass the route climbs a trailless ridge. A flyover only works when there is a set trail to trace. Without one, the line would be a guess, and a guess could send you the wrong way on the mountain. Use the step-by-step route with a good map and GPS track instead.
See the trail on video
No video yet
We haven’t found a good video of this route that matches the way we describe it. The route strip, junctions and 3D flyover show the way in the meantime.
Other routes
Every way up UN 13,350 we list, with its class.
UN13,350 Southwest Ridgethis routeClass 2+ 12.4 mi
This describes the route on a dry summer day. Most 13ers see few people, so there may be no one along behind you. Check recent conditions the week you go, carry a map, tell someone your plan, and turn around when the day tells you to.