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 · Tour de Abyss Loop
Overview
The Tour de Abyss is a loop over Mount Bierstadt, the Sawtooth and Mount Blue Sky, starting and ending high on the Mount Blue Sky road. You drop into the basin between the peaks, climb Bierstadt's east ridge, cross the Sawtooth to Blue Sky's west ridge, and finish on Blue Sky's summit. It is about 5.75 miles with about 3,000 feet of gain.
This is a Class 3 route with real exposure. Bierstadt's east ridge has a steep, exposed crux around Point 13,641, and the Sawtooth has narrow ledges and a gendarme with harder climbing. It is for experienced scramblers who are good at finding their own way on rock. It is much harder than Bierstadt's standard trail from Guanella Pass or the road-side trails on Blue Sky.
Plan on 6 to 9 hours. The route is short in miles but slow on the ridges.
Plan of the day
Start by
Early, by 6 a.m. if the road and your reservation allow. You are above treeline the whole day.
Turnaround
If you are not on Bierstadt's summit by about 11 a.m., or clouds are building, do not start the Sawtooth. It is hard to retreat from quickly.
Crux
Point 13,641 on Bierstadt's east ridge, where a ledge on the right bypasses a Class 5 section and a steep pitch leads back up. The exposed downclimb off the point and the Sawtooth gendarme and ledges are close seconds.
Route-finding
Hard. You must find the right gully off the saddle, the ledge around Point 13,641, and the notch and ledge on the Sawtooth. Study the route ahead at each saddle.
Water
Only the small stream in the basin below Bierstadt's east ridge. Carry 2 to 3 liters and treat any water you collect.
Leave Interstate 70 at Idaho Springs (Exit 240). Colorado 103 leads south about 13.5 miles to Echo Lake. At the Mount Blue Sky road entrance, you will need to show your reservation. Drive about 14 miles up to the summit parking lot, which has restrooms.
You can also park at a small pull-off on a road corner at about 13,300 feet, a little over 11 miles above Echo Lake. Parking at the summit lot requires a reservation made in advance. The road is only open in the warmer months.
TundraRidgeScramblingExposed 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
Summit parking lot 14,130' · 0 mi
Leave the lot and head down toward the saddle between Mount Blue Sky and Epaulet Mountain. The loop ends back here, just below Blue Sky's summit.
Watch for: If you start from the 13,300-foot corner, do not take the small path to the nearest gully. Go down to the saddle first.
2
Top of the gully 13,100' · 0.9 mi
Look on the saddle's west side for the top of a gully that drops west toward Bierstadt. Turn right into it.
Watch for: Make sure you are in the correct gully before heading down.
3
Base of the gully 12,300' · 1.4 mi
Work your way down through the rock for about 800 feet to the basin floor. Take your time.
Watch for: Loose rock. Keep your group close so dislodged rocks do not build speed.
4
Stream crossing 12,250' · 1.8 mi
Walk west across the basin. Cross the Abyss trail and then the small stream that drains the basin. The foot of Bierstadt's east ridge is just past the stream.
Watch for: Last water on the route.
5
Crest of Bierstadt's east ridge 13,100' · 2.3 mi
Climb about 800 feet of Class 2 slope to the ridge crest. Go right and scramble across the ridge's first two points.
6
Point 13,641 13,641' · 2.8 mi
The ridge crest here has a Class 5 section. Bypass it on a grassy ledge to the right, below the cliffs on your left. Then climb a steep pitch back to the ridge and scramble to the top of the point.
Watch for: The pitch back to the ridge is steep. Go slowly to keep it at Class 3.
7
Downclimb off Point 13,641 13,450' · 3 mi
Getting down off this point is exposed and steep. Look to the left of the crest for easier ground. Near the bottom, move past some big rocks to reach easier terrain.
Watch for: Exposure is serious here. Test holds before you weight them.
8
Bierstadt summit 14,066' · 3.4 mi
Pass the last points on the ridge. Climb about 200 feet of large blocks to the summit. The Sawtooth and Blue Sky are ahead to the north and east.
Watch for: Check the time and weather before you start the Sawtooth.
9
Saddle and gendarme 13,300' · 3.8 mi
Head down the north side, staying right of the crest, to the saddle near 13,300 feet. Just past the notch is a large rock tower with the hardest climbing. Climb only as far as you are comfortable, then go right and scramble around its east side.
Watch for: Study the route from above before you reach the notch.
10
Notch in the Sawtooth 13,450' · 4 mi
Just short of the next rock outcrop, go left up a gully that ends at a notch in the ridge. Go through the notch and turn right onto a ledge on the west side.
11
Sawtooth ledge 13,600' · 4.2 mi
The ledge is narrow at first, then gets wider and easier. To pass the last ledges, either drop a little or climb a bit and cross above a rock wall. Climb the ledge to about 13,600 feet, then turn right and go up talus to the top of the Sawtooth.
Watch for: Exposed. Stay focused until you are off the ledge.
12
Cairned trail on Blue Sky's west ridge 13,800' · 4.6 mi
Walk east toward Blue Sky's west ridge and pick up a trail with cairns. Continue to a hump on the ridge and a notch next to it. Drop slightly right and follow the cairns east, below the crest.
13
Mount Blue Sky summit 14,268' · 5.6 mi
For most of the way, the trail runs below the ridge. When the summit comes into view, walk almost to the road corner and climb the last 100 feet to the top.
Getting down
The summit parking lot is just below the top. Cars left at the 13,300-foot pull-off are nearly a mile away, southeast and downhill.
If things go wrong
Before Bierstadt, the easiest way out is back across the basin and up the gully to the saddle. From Bierstadt's summit, the standard trail down the west side leads to Guanella Pass, far from your car, so only use it in an emergency and plan a ride. Once you are on the Sawtooth, it is usually fastest to keep going to Blue Sky's west ridge. Do not start the Sawtooth in bad weather. In an emergency call 911 if you have signal.
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.
