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.
Combo route · Bierstadt, Sawtooth, Blue Sky
Overview
This is a long Class 3 link-up of Mount Bierstadt and Mount Blue Sky across the Sawtooth, a rugged ridge between the two peaks. You climb Bierstadt by its standard west slopes trail, drop north along the ridge, scramble past a large rock tower, traverse ledges across the Sawtooth's west face, then boulder-hop the west ridge of Blue Sky to its summit. You return to Guanella Pass by a gully and a creek valley, not over Bierstadt again.
This is not a route for beginners. It needs real Class 3 scrambling, some exposure, careful route-finding, and the fitness for a long day above treeline. It is far harder than the standard Bierstadt hike. The trip is about 10.5 miles round trip with about 3,900 feet of gain.
Expect 9 to 12 hours car to car. The descent through the willows can be slow and wet.
Plan of the day
Start by
By 4:30 or 5 a.m. You spend most of the day high on exposed ridges, and the Sawtooth is not a place to be caught in a storm.
Turnaround
If you are not on Bierstadt's summit by about 8:30 a.m., or clouds are building, skip the Sawtooth and go back down the standard trail. Once you are on the Sawtooth ledges, the fastest way out is often to keep going.
Crux
The gendarme close to the ridge's low point north of Bierstadt, and the ledge traverse across the Sawtooth's west face. Both need Class 3 moves, and the ledge starts narrow.
Route-finding
Hard in places. Study the ridge from Bierstadt's summit. On Blue Sky's west ridge, look for cairns and trail pieces. On the descent, the trail through the willows along the creek is easy to lose.
Water
None on the ridge. You will pass the creek on the way out. Carry 3 liters or more for the day and filter any creek water.
From Interstate 70, take the Georgetown exit and drive through town. Take the Guanella Pass Scenic Byway, as signed, for about 12 miles up to the pass, near 11,700 feet. There are two large paved lots. The Bierstadt trail leaves from the east side of the road. The lot on the west side has restrooms.
From the south, take U.S. 285 to the town of Grant. There, head north on the Guanella Pass Scenic Byway; the pass is about 13 miles up. The road is paved. The lots fill very early on summer weekends.
TundraRidgeTalus and screeScramblingExposed 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
Guanella Pass trailhead 11,670' · 0 mi
Begin on the Mount Bierstadt trail, which leaves from the road's east side. It heads east across a broad valley toward the peak.
2
West slopes of Bierstadt 13,000' · 2.5 mi
Follow the standard trail up Bierstadt's west slopes. The trail is well worn and climbs steadily on open ground.
Watch for: Pace yourself. The hard part of the day comes after the summit.
3
Summit of Mount Bierstadt 14,066' · 3.5 mi
Reach the top of Bierstadt. Look north to see the Sawtooth and the rough ridge that joins it. Take time to study the route ahead.
Watch for: Decide here if the weather and your group are good for the traverse.
4
Descend the north ridge 13,600' · 3.8 mi
Leave the summit heading north toward the Sawtooth. Stay a bit to the right (east) of the ridge crest on loose rock. Keep checking the terrain ahead as you go down.
5
Gendarme near the low point 13,300' · 4.1 mi
Near the ridge low point, pass a couple of rock points on the right. A big rock tower comes into view. Walk up to it from a notch. You can climb straight over it or go around it on the right. Both ways need Class 3 moves.
Watch for: Test holds. Rock here can be loose.
6
Notch in the ridge 13,400' · 4.3 mi
Past the tower, cross a gully and another rock outcrop. Go left and climb to a notch on the ridge.
7
West-side ledges 13,500' · 4.5 mi
Go through the notch and turn right. A ledge takes you across the Sawtooth's west side. It is narrow at first, then gets wider and easier. Near the end, go right, climb a little, cross under rock slabs, and go up a dirt ramp.
Watch for: The first part of the ledge is exposed. Move with care.
8
Exit the ledges 13,600' · 4.7 mi
Pass a large boulder that fell from above and leave the ledges near 13,600 feet. The ground gets easier.
Watch for: Rockfall is possible here. Do not linger under the cliffs.
9
Top of the Sawtooth 13,700' · 4.9 mi
Turn right and walk up talus to the top of the Sawtooth. From here you can see the west ridge of Mount Blue Sky to the east.
10
Blue Sky west ridge 13,850' · 5.4 mi
Head east, drop a bit, then climb to a hump on the ridge. When you reach a notch, step down a little to the right and follow cairns below the crest.
11
Boulder field on the ridge 14,000' · 6 mi
The last mile is mostly boulder-hopping. Cairns and short trail pieces help. Stay with the ridge until you can see the summit.
12
Summit of Mount Blue Sky 14,268' · 6.4 mi
Meet the tourist trail near the top and follow it to the summit. There is a road and buildings nearby, so expect other people.
Getting down
Do not go back over Bierstadt. Retrace your steps west along Blue Sky's ridge to its west end, with the Sawtooth on your left. Instead of heading onto the Sawtooth, walk northwest into the open ground between the Sawtooth and Mount Spalding. Keep going down until the slope funnels into a gully that drops toward Scott Gomer Creek. The gully gets steep fast and is loose, though a rough path runs through much of it. Near 12,300 feet, leave the gully on the left and pick up a path that works down through ledges and ends in a clearing next to the creek. Walk across it and into the willows. Keep the creek on your right and go west for about a mile on a thin, easy-to-lose path until you meet the Bierstadt trail. Follow it back to the pass.
If things go wrong
Before the Sawtooth, the safest bail is back down Bierstadt's standard trail. Once you are past the gendarme and on the ledges, going forward is usually faster than going back. From the top of the Sawtooth, the gully descent toward Scott Gomer Creek is the quickest way below treeline. In a storm, get off the ridge crest and head down at once. Call 911 if someone is hurt, and expect a long wait for help on this terrain.
Other routes
Every way up Mount Blue Sky we list, with its class.
This describes the route in its usual season. Distances and elevations are close estimates for planning. Snow, ice, rockfall, a washed-out road or an afternoon storm can make it a very different climb. Check recent conditions the week you go and turn around when the day tells you to.
