OverviewSomewhat overshadowed by it's nearby cousin, the Couloir des Cosmiques, the Glaciar Rond is nonetheless a "must-do" Chamonix ski for those falling between the Expert and Extreme skier classes. Like all popular routes of this difficulty level, this route has been known to see moguls and you will be unlikely to get anything near the first track down it.
A route not to be taken lightly. A fall anywhere within the 800m from start to finish could be deadly.
Chamonix skiers are nowadays completely bonkers, taking far too much risk. Evaluate the safety of this route on your own versus following the tracks that will certainly already be there. Keep in mind this route, like all others of the similar grade, are never completely free from objective danger (avalanches, rocks under the snow surface, etc.)
If you have to break a trail on this one, you either 1) really REALLY know what you're doing 2) are really REALLY nuts (e.g. there is extremely high avo danger or you are trying it at the wrong time of year) or 3) you have taken the first Midi lift up after a storm and are really REALLY lucky to be the first in (doubtful!). But here's the route from start to finish anyway:
Take the Midi up climb down the arete, bearing as high as possible skier's right around the Midi South Face. Keep as high right as you can, aiming for the Abri Simond refuge, located at the end of the Cosmiques Arete. You normally need to walk uphill carrying skis for about 10 minutes and can downhill traverse/skate the rest.
Just to the looker's left and slightly downhill of the refuge, find the exposed and sometimes sketchy snow traverse ledge that leads back around, under the refuge high up the West face of the massif. Some or all of this might be a walk, versus a ski. If you find the right way you will arrive at the top of the wide and steep Glaciar Rond.
The Hanging Glaciar
Looking down from this spot - often with shaky knees - you can see the steep glaciar flattens ohh too breifly and then disappears at a rollover. It will not comfort your nervous to know that the rollover is a nearly vertical cliff over 200m high. If you fall anywhere in the 400m drop that you see, you need to be sure to stop your cartwheeling body in that ohh too brief shallow zone otherwise you will surely die falling off that cliff. Falling here without subsequent death has been done, but let's not risk it OK, so turn carefully.
Anyway you can roam free on this wide and sometimes very enjoyable slope, but you want to aim for the indistinct start of a couloir on the skier's left side around 3/4 down.
By the way, The true "Glaciar Rond" actually begins only after the sheer cliff that you aren't going to fall over. This top hanging glaciar is technically unnamed.
The Exit Couloir
The start of the couloir is far from distinct and the best way in depends on the conditions. Sometimes a short rappel is required here.
Once in the couloir you can't really get lost - it just goes down, down, down. Luckily it is fairly straight so if you were to fall here you may not hit anything nasty... but let's not try.
The couloir is a sustained 40 degrees all the way down.
Return to the Plan de l'Aiguille
You end up just below the Couloir des Cosmiques, so from here it's the same way out.
Once on the Bossons Glaciar, traverse towards Chamonix, hugging the cliffs on the skier's right. This zone is sometimes a jolly ski, sometimes a messy, hair-rasing glacial mess requiring you to rope together and sometimes downclimb using crampons and an axe. Bring the whole kit on this one.
Keep traversing back towards the Plan du L'Aiguille midstation bearing high skier's right. Do not dilly-dally in this obvious avalanche-prone area. Depending on snow conditions and who built the track, you will probably need to climb slightly, usually with skis still on, side-slipping upwards, to get above a cliff band.
Near the old midstation of the predecesor to the Aiguille du Midi cablecar, you can either keep on a high and very much "uphill" traverse to reach the Midi midstation, or continue all the way down to the Tunnel du Mont Blanc. Be sure to check out the snow conditions and be advised that it's very steep in parts and route finding down there is a whole other mess in itself - consult a guidebook and study it in advance.
If you elect to take the whole shebang down to Cham', you'll end up at the tunnel entrance. From there you can walk across the parking lot and continue down to the Midi base station via a much less steep path through the forest. You end up right in the Midi car park, so why not do the Couloir des Cosmiques on the next bin up?