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Mt. Blanc: Trois Mont Route

Extremely Difficult


4.6 mile 7.3 kilometer point to point
53% Runnable
Extremely Difficult


Ascent: 4,791' 1,460 m
Descent: -861' -262 m
High: 15,686' 4,781 m
Low: 11,607' 3,538 m


Avg Grade: 23% (13°)
Max Grade: 95% (44°)


No Dogs
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Trail shared by Jacob Winey

A super-scenic, glaciated route up Mt. Blanc starting from the Cosmiques Hut.

Jacob Winey

Features Views

Tends to change year by year and by season—make sure you know what you're getting into and check with the Chamonix Haute Montagne if you're unsure.

Runner Notes

Not advised for trail running, but if you feel like showing Killian Jornet who the real king of the mountain is, go for it.


You can either start this route from the Cosmiques Hut, or you can camp in the Col du Midi. If you choose to camp, keep some room between you and Tacul, as it is known to drop large seracs down into the col.

Wake up nice and early for your alpine start. If you're staying at the hut, you can choose between a 1 AM, 3 AM, or 5 AM breakfast. Once you get moving, cross the Col du Midi and start climbing up Mont Blanc du Tacul. The route up should be fairly well set in, unless there's been recent snow. It's important to stay on the route set by the guides here since the north face of Tacul has crevasses larger than you can imagine. If you're lucky, there may even be a few ladder crossings to clear crevasses.

The route will switchback up Tacul, where you'll have a short descent off the summit and onto the shoulder between Tacul and Maudit. Cross the shoulder to the base of Maudit where the trail will begin switchbacking up and around crevasses again. This face of Maudit gets considerably steeper than Tacul, which means that the top half doesn't have as many crevasses, but the switchbacks end and you have to snow/ice climb up the rest of the face. That'll be the steepest climbing of the day.

Once you get off the north face of Maudit, the route traverses over the Col du Maudit, where you can see the rest of the climb to the summit of Mt. Blanc.

This part of the climb offers staggering views over the Italian Alps and even into the Swiss Alps. Look for the Matterhorn to the south east. The other staggering part about this section is the altitude. Prepare to feel sluggish and exhausted as you break 15,000 feet. The switchbacks to the summit are mellow compared to everything else on the route. If it's a clear day, expect there to be a crowd on the summit, so there will be plenty of people to celebrate with.

Flora & Fauna

Not much—you'll be on glaciers the whole time.

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in France


33 Views Last Month
841 Since Aug 28, 2017
Extremely Difficult



The north face of Tacul as seen from the Cosmiques Hut
Sep 17, 2017 near Chamoni…, FR
From the side of Maudit, early in the morning.
Sep 17, 2017 near Chamoni…, FR
Looking down the Bosses Ridge from near the summit of Mt. Blanc
Oct 10, 2017 near Chamoni…, FR
The summit push up Mt. Blanc, early in the morning.
Sep 17, 2017 near Chamoni…, FR


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