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Traverse of Les Drus to Aiguille Verte

Updated: Jan 7

The Integral ridge spanning the Flames De Pierre to Aiguille Verte should be one of the iconic Chamonix alpine climbs. Over the course of 5 days, Daniel Joll, Chris Warner and Alastair McDowell traversed the granite skyline ridge connecting Les Flammes de Pierre, Les Drus, Aiguille Sans Nom and Aiguille Verte, descending via the Moine Ridge to Couvercle Refuge. The 3 days of climbing involved traversing 3 kilometres of complex ridgeline, bagging 4 summits, ascending over 2000 metres of technical terrain, with 2 bivouacs just below the summits of Petit Dru (3700m) and Aiguille Sans Nom (3950m).


I was on the bus, arriving in Chamonix on the final leg of my long journey from New Zealand, admiring the glistening summits four thousand metres above the valley. Dan Joll sent me a message, a 5 day weather window was rolling in, and he was packing for a big mission. A ridge traverse of Les Drus, a linkup he had been dreaming of for several years. I was keen, it seemed like a great way to acclimatise to the great mountains of the Mont Blanc region, living on a ridge line for several days, living and breathing French air. I mentally treated this as a tramping trip instead of a trail run: although the extra weight would slow us down making steep climbing harder, I remembered how refreshing it is to be relaxed at the end of the day as darkness approaches, setting up a bivouac on the summit, instead of stressing about the long descent.

This would be my first climbing experience in Chamonix, and as soon as we began the approach beyond Montevers train station, I would find all the rumors of The Alps to be true. Industrial scale ladders bolted to the cliffs, Hundreds of trekkers and guided clients swarming across the glacier ice, checkered table cloths spread across boulders laden with baguettes & wine. But after scaling ladders towards Chapeau Refuge, we would have the mountains to ourselves.

At daybreak we left our grassy bivouac at the base of Flammes de Pierre to begin the mile-long ridge traverse towards Petit Dru. Climbing was rapid, mostly easy scrambling but with complicated route finding. Un-acclimatised and still mildly jet lagged, above 3000m I started to suffer a strange brand of fatigue, gasping for breath after pulling each of the strenuous rock steps with the heavy pack. Daniel and Chris traded long simul blocks, stretching the single rack 100-150m per pitch.

Just after sunset we reached a plush bivouac spot 50m below Petit Dru and dropped our loads with relief, a 15 hour day. I lead off in search of snow to melt, fortunate to find a cave full of ice smears to pain stakingly chip away. Despite our altitude of 3700m, our lightweight bivvy setup kept us comfortably warm. It consisted of a 650 gram quilt sleeping bag and a 2 person bivvy bag with openings at each end to allow 3 people to fit. The foam from our packs and lightweight air matts kept us lofted from the rocky base.

Early the next morning after a spectacular daybreak, I discovered another Euro clich' on the summit of Petit Dru, a statue of the Virgin Mary gazing out to the valley where Chamonix was just waking up. Traversing to Grand Dru involved a single abseil and two pitches to our second summit via a thrutchy chimney made easier by a fixed rope, and made harder by a large backpack. By now every crux section would not leave me in such fits of deep breathing – the time sleeping up high was helping my acclimatisation. Instead of rushing over the summit of Grand Dru, we used the morning sunshine to dry our wettened sleeping bag and brew up hot drinks for about an hour. It can seem counter-intuitive to spend such time resting but we realised keeping hydrated on a long route was key.

Traversing between the Grand Dru and the Arete de Sans Nom was one of the chossiest stretches of the route. Six raps from the summit brought us below the Pic Sans Nom, where a loose diagonal traverse through unknown and rarely travelled ground landed us in a stripped back gulley of rotten snow raining with stone-fall, and gritty granite slabs. Two heady pitches eventually freed us from this dangerous section, which in June or July would be an easy snow plod.

Mist & fog now encircled us as we quested upwards to Aiguille Sans Nom, Daniel relying on his memory of the face to guide me up the correct line of rock ribs and snow couloirs. With my one Petzl Quark I climbed gritty mixed terrain and grunty sections of crack climbing in boots & gloves to reach the summit ridge of Aiguille Sans Nom. No ideal bivvy spot was to be found as our perfect forecast deteriorated into light snow and darkness closed in. As a result, Aiguille Sans Nom is now equipped with a brand new bivvy platform just below the snow crest.

Running-shoe style boots are becoming quite popular in the Alps, however the snow crest connecting upwards to Aiguille Sans Verte is renowned for having hard blue ice on the long traversing sections. We did not regret our heavier full-shank boots here, which was still precarious on some downclimbing sections with just the one axe. Flexible footwear and aluminium crampons would not have been a good time. Cresting Aiguille Verte’s dome-shaped summit via the crisp snow arete was textbook mountaineering joy, and the outlook of all the Alps from this position in the morning sun was superb.

Here our plans to continue to Les Droites, another day’s climbing, were foiled; the descent slopes were completely bare in the late season. The Whymper Couloir notorious for rock-fall was also bare. Instead we used the longer yet safer Moine Ridge for descent, following many cairns and 10 abseils just below the crest. Moine Ridge is rich in valuable quartz crystals and the evidence of crystal hunters mining efforts were spread across the ridge. Crossing the broken bergschrund was a relief, after 6 hours of very loose down-scrambling.

The Mont Blanc region is full of swaths of immaculate granite, but as we found on many sections of this traverse, that perfect granite is often broken into much smaller pieces. Even so this traverse covered some incredible and complex ground, multiple summits, high & comfortable bivvies, quality climbing at moderate grades, with great vantages of Grand Jorasses & Mont Blanc, and deserves to be a Chamonix classic. We realised that despite the current push towards light & fast alpinism, occasionally going slower & heavier gives you more time to relax and enjoy the mountains, rather than simply rushing through them. Don’t come and go. Come and stay.

Route Beta & Strategy

The fact that this traverse has seen only 4 ascents to date (that we know of) is strange considering how many iconic summits the route takes in and the moderate difficulty of the climbing across the ridge. The following info hopefully will make future ascents easier.


While you could get away with light axes , crampons and running shoe style footwear we choose to take one proper axe each, light boots and steel crampons. I would recommend sticking with the heavier axes and crampons due to the snow and ice climbing on the Sans Nom - Aiguille Verte ridge. This can contain blue ice and would be fairly sketchy in alloy crampons or with an ice axe that couldn't swing properly into hard ice.


If you're a party of two 1 x 60m rope is all you need. Parties of 3 could take 2 x 50m ropes. You need to make some 30m rappels on both the Dru and the Moine Ridge. Rack. Single set of cams sizes red C3 - blue C4. Single set of nuts. 2 x pitons. 8 quick draws (60cm ones are ideal) 2 x 120cm slings. 2 x cordalette's. 2 x ice screws. Spare cord for descent rappels or retreating.

Climbing Strategy

Being Chamonix no doubt it won't be long before someone does this traverse in a day, which would be fully possible. We spent two medium sized days climbing and a short day for our third to reach the Verte summit followed by the time to descend. That being said, the climb covers some excellent terrain with fantastic bivy spots and enjoying this route over several days is a worthwhile experience. We opted for the relaxed approach, stopping for brew breaks each day and enjoying the excellent scenery. The maximum rock difficulties of the full route are 6b but you need to be comfortable moving fast on typical 5c - 6a terrain. We climbed most of the route in alpine boots and gloves. We opted for rock shoes for the higher part of the Flammes De Pierre and Les Drus.

The best places to bivy are, near the end of the Flammes de Pierre. Below one of the few rappels you need to do towards the end of the Flammes, look below you and you can see a well formed bivy spot (finding snow to melt here will be hard late summer). The next good bivy locations are near the summit of the Petit Dru. The Petit Dru summit bivvies are excellent. They also put you close to snow which is going to be handy as there are not alot of locations for getting water on the Flammes if you are climbing the route late summer. Either depart Montenvers on the first train start climbing and hopefully make it to the summit of the Petit Dru or as we did walk in to the base of the Flamme de Pierre and bivy there ( approx. 3 hours)

The next day climb to the summit of the Petit Dru 12 - 15 hours if your moving at a moderate pace.

The following day head to the summit of the Aiguille Sans Nom via the Arete Sans Nom. There are not many good bivy spots between Les Drus and Sans Nom. There are two good bivy spots near the Sans Nom summit. One right on the ridge that we created and sleeps 3 people. Another on the Southern side of the ridge part way along. You could also cut into the snow anywhere along the ridge but we preferred to sleep on the rock and be a bit warmer.

As an alternate you could also continue on to the summit of Aiguille Verte (approx. 1.5 - 2 hours) and then take the bivy at the very top of the Moine ridge below Aiguille Verte summit. Once on the Moine ridge there are many bivy spots and you could basically stop anywhere.


If you are early season when the Whymper Couloir is in condition this is your fastest way down the mountain. However if you are climbing the route late summer as we did descending the Wymper is not a safe option. Therefore you will need to take the longer but safer Moine Ridge. This will take 5 - 7 hours for most parties to descend. (maybe longer if you get off route) The Moine ridge has recently been cained making route finding much easier. From Couvercle hut, 3 hours to Montevers Station, or if not taking the train an extra 1 hour to Chamonix.

Objective dangers

The two major objective dangers of this route are climbing the gully to the col between Pic Sans Nom and Aiguille Sans Nom (if its late season and dry) and the Whymper Couloir. You will need to take the level of rock fall into account before heading up or down either of these two couloirs.

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