Arête des Cosmiques, Chamonix: A Comprehensive Climbing Guide

The Arête des Cosmiques is a celebrated alpine route in the Mont Blanc Massif, offering climbers a thrilling combination of rock and ice challenges amidst breathtaking scenery. Its accessibility via the Aiguille du Midi cable car and its moderate difficulty make it a popular choice for climbers seeking a classic alpine experience.

Essential Reading: The Ultimate Guide to Backcountry Emergencies in Chamonix

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Sunset at the Aiguille du Midi viewed from the Vallee Blanche

Sunset and views of the North Face of the Aiguille du Midi. Would like it printed? Click here for more!

Overview

Location: Aiguille du Midi, Chamonix, France
Altitude: 3,842 meters (12,605 feet)
Difficulty: AD (Assez Difficile) – Fairly Difficult
Length: Approximately 200 meters (656 feet)
Elevation Gain: Around 200 meters (656 feet)
Time Required: 3 to 4 hours (without traffic delays)
Best Season: June to September (Note: in high-summer the rock can get too dry and crumbles - always check in with the La Chamoniarde for current mountain conditions).

Approach

Begin your journey by taking the Aiguille du Midi cable car from Chamonix to the upper station at 3,842 meters. From the station, descend the exposed snow ridge to reach the Col du Midi at 3,532 meters. This descent can be steep and requires caution, especially after fresh snowfall. Once at the col, proceed towards the Refuge des Cosmiques, which serves as the starting point of the climb. It's recommended to take an early cable car to beat the 'traffic'.

Two mountaineers walking down the Midi Arete to the Vallee Blanche

A Chamonix Classic - the "Midi Arête". Interested in getting a print? Click here for more!

Route Description

1. Descent from the Aiguille du Midi Station

Upon exiting the Aiguille du Midi cable car station, you’ll begin with a descent down the exposed snow ridge leading to the Col du Midi. This section can feel intimidating, especially if you’re not accustomed to altitude. The descent is narrow, requiring careful footwork. You may want to rope up with your partner, particularly in icy or windy conditions. As you reach the col, keep a steady pace and make sure your crampons are securely fastened for traction on the snowy path.

2. Approach to the Start of the Ridge

From the Col du Midi, head towards the Refuge des Cosmiques. This portion is relatively flat and serves as a warm-up for the climb. You’ll pass by sections of snow and rock; keep an eye on the weather here, as sudden winds or clouds can obscure visibility. Once at the base of the ridge, secure your gear and prepare for the first section of mixed rock and snow. Bare in mind that you're on glacier territory now. Rope up and follow tracks, keep an eye on crevasses.

3. Initial Ascent on the Ridge (Grade ll)

From the old Abri Simond Hut, opposite the Cosmiques Refuge, start climbing along the east side of the ridge. This section is characterised by simple scrambling, mostly on solid rock with occasional snow patches (or more snow depending on the time of year). The climbing here is straightforward but be cautious as the rock can be slippery from snow or ice, or crumbly in high-summer. This part is usually less exposed, allowing for a good rhythm to build confidence as you move upward. Keep roped up if the conditions are questionable.

4. The First Gendarme and Traverse Options

The first major obstacle is the initial gendarme, a prominent rocky tower along the ridge. Here, you have two main choices:

Abseil Option (recommended): Many climbers choose to rappel down this gendarme to reach the base. This descent is straightforward but requires careful handling of the rope and anchor points. Double-check each attachment for safety, as a crowded route may mean worn spots on commonly used anchors. You may find it easier to down climb this section whilst being roped up.
Traverse Option: If you’d rather avoid the rappel, you can traverse around the east side of the gendarme. This involves some exposure and requires careful footwork. The traverse is slightly more technical, graded at around III, but often faster if you’re comfortable with exposed movement.

5. Intermediate Sections of Mixed Rock & Snow (Grade lll)

Continue along the ridge, which now alternates between rock scrambling and snow patches. This section is often roped due to the exposure and changing terrain. The holds here are generally good, but snow can hide some of the ideal placements. Take your time with each step, especially if the route is icy. It’s a good idea to carry quickdraws and slings to clip into the frequent fixed points along this route, particularly as you approach the next gendarme.

6. The Crux (Smooth Rock Face with Bolt Protection)

The crux of the route is a steep, smooth rock face that presents the most technically demanding climbing. This section is protected by a bolt around 5m above the start and has a noticeable crack, which serves as a natural guide for hands and feet. Use the crack and any existing holds (carved for crampons by mountain guides), but be ready to pull yourself up confidently. A few quick-draws are helpful here to secure each movement, and it’s advisable to assess the bolt and ensure it’s stable. The crux is short but can be physically demanding due to the exposure and altitude, so don’t rush this section. After the bold, move around the right of the rock to the top. Here is another anchor to secure your partner from.

7. Traverse to the West Side and Entry into the Couloir

After the crux, you’ll reach a series of traverses that lead to a snow-filled couloir. The traverses before the couloir are the most exposed sections of the journey. Make sure to travel slowly, with distance to your partner and secure your rope where possible. The couloir is typically ascended in 1-2 pitches, depending on your comfort level. Establish belays on the right side to secure each pitch. The snow here can be deep, and it may require some post-holing, particularly later in the season. The couloir climb is straightforward but exposed, so concentrate on footwork and stability with your ice axe. Check that each hold or axe placement is secure, especially in icy conditions.

8. Final Rocky Blocks & the Metal Ladder to the Aiguille du Midi

As you near the top, you’ll encounter large rocky blocks that require careful scrambling to cross. These blocks are often icy, so keep your gloves on and be mindful of each hold. This section is less technically demanding but can feel tiring due to the altitude. Once you’ve crossed the blocks, you’ll come to the final metal ladder (arguably the scariest part of the climb), which leads directly to the Aiguille du Midi terrace. This ladder marks the end of the climb and provides a unique, exhilarating finish to the route, with views stretching across the Mont Blanc massif.

Additional Tips for the Route

Weather Precautions: Always be aware that weather changes can happen rapidly. Check conditions before heading out, as storms or sudden clouds can make this route more dangerous.
Timing: Start early, as the route can get crowded, and climbers may bunch up at the crux or at belay points with wait times up to 45-60 minutes.
Respect Other Climbers: The Arête des Cosmiques is popular, and climbers of all levels attempt it. Be mindful of climbers both above and below you, especially at exposed or narrow sections.

Sunrise views from a successful Mont Blanc ascent. Click here for more!

Final Note

The Arête des Cosmiques provides a unique blend of technical rock and alpine snow challenges at high altitude. It’s accessible, yet still offers a true alpine experience with moments of exposure, fantastic scenery, and a sense of accomplishment when you reach the Aiguille du Midi terrace. Prepare thoroughly, go with a reliable partner, and enjoy every part of this alpine classic!