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Cosmiques Arête 

YDS: 5.6 French: 4c Ewbanks: 14 UIAA: V ZA: 12 British: S 4b AI2 M4

Type:  Mixed, Ice, Alpine, 8 pitches, 1000', Grade II
Original:  YDS: 5.6 French: 4c Ewbanks: 14 UIAA: V ZA: 12 British: S 4b AI2 M4 Mod. Snow [details]
Page Views: 3,568
Submitted By: Dan Flynn on Mar 4, 2012  with updates from Rui Ferreira and 1 more

You & This Route  |  Other Opinions (31)
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enjoying some airy crack in front of the tourists


The Classic Climb. AD, Grade II, mostly snow and moderate alpine climbing, with a few sections of strenuous mixed climbing (in winter) or easy rock.

The start up from the Cosmiques laboratory is quite easy, no need to rope up. The beginning of the arete apparently is a slab in summer, but an easy snow slope in winter. From the second peak, two short rappels take you down to the base of the third peak. Easiest route is around to the right, also possible to go straight up it (but need to abseil again).

A short chimney pitch was the crux for us. The guidebook calls it 4c... felt like M5 to me!

Traverse around the corner to the Chamonix side of the ridge, and don't get distracted by the gully with the small roof.. instead head further to the left for the last, brilliant pitch of mixed snow and ice climbing. Really a blast!

Finish on a shoulder in view of the platform of the cable car station. Walk over and up the metal stairs to top out on the platform, doing your best to ignore the cameras (why yes, I am a famous alpinist...).


From the cable car station, walk down the steep ridge (put on your crampons, you have them!), and turn down the easy slope towards the Refuge de Cosmiques. Hike up the slope towards the abandoned Cosmiques laboratory, and follow the obvious line up the arete.

Since the finish is on the cable car station, it makes a popular round trip!


In winter, we used about 3 short screws and a bunch of cams and nuts. There are a few ancient pitons to clip as well. A single 60m rope is fine, and 50m would probably work.

Photos of Cosmiques Arête Slideshow Add Photo
Rock Climbing Photo: End of the arete
End of the arete
Rock Climbing Photo: crux
Rock Climbing Photo: View from the base of the rappel, mid-route.
View from the base of the rappel, mid-route.
Rock Climbing Photo: beginning of the Cosmiques
beginning of the Cosmiques
Rock Climbing Photo: Cloudy day on the Cosmiques
Cloudy day on the Cosmiques
Rock Climbing Photo: route in dry conditions
route in dry conditions
Rock Climbing Photo: Views
Rock Climbing Photo: On the ridge - 6/20/2012
On the ridge - 6/20/2012
Rock Climbing Photo: What a View - at the top 6-20-2012
What a View - at the top 6-20-2012
Rock Climbing Photo: On the ridge - June 20, 2012
BETA PHOTO: On the ridge - June 20, 2012
Rock Climbing Photo: Enjoying the view! With Triangle du Tacul and Mont...
Enjoying the view! With Triangle du Tacul and Mont...
Rock Climbing Photo: In the middle somewhere
In the middle somewhere
Rock Climbing Photo: On the first rappel
On the first rappel

Comments on Cosmiques Arête Add Comment
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By Scott O
From: California
Apr 21, 2015

They say it's doable in almost all weather conditions (it is), however blowing snow/sleet mix will HAMMER you on this route. It's quite exposed to weather, and we did it in suboptimal conditions. Snow was loose, the "easy rock" was covered in verglass, and the route was still crowded! Get up early (need to stay at the hut as we took the first lift) and beat the crowds on this ultra classic route.
By Chris C.
From: Seattle, WA
Sep 4, 2016
rating: 5.6 4c 14 V 12 S 4b AI2 M2+

Much easier done with crampons than without. Because it is a classic introductory mixed route (well deserved!), crampon footings are deeply embedded in the rock in tricky spots. The crux slab is essentially walking up a ladder with crampons on. Without crampons, the crux is about a 5.6-7. I did not find dry tooling necessary, so I am not sure why the route is graded as M4.

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