Grépon : Charmoz-Grépon traverse

• 1^st traverse of Grands Charmoz (NW-SE) : September 10, 1887 - P. Burnet, T.P.H. Jose, François Simond.
• 1^st traverse of Grépon (N-S) : August 18, 1892 - John Norman Collie, Geoffrey Hastings, Albert Frederick Mummery, Charles Henry Pasteur.

Approach 3h30

From the Plan d’Aiguille cable car station, follow the path which traverses the Blaitière glacier and leads to the Nantillons glacier, following various cairns.
Variant: If you are coming form the Midi Plan hut it is best to take the lower path directly E from the hut, and finish up the moraine of the Nantillons glacier to its high point.

Cross to the true right bank of the glacier (risk of stonefall, cross low down and quickly!) arc upwards and go to the right to reach the Rognon des Nantillons (at the first 1/3 of the Rognon), where the glacier levels against it, at the foot of some seracs.
Climb to the top of the Rognon, firstly by easy steps on the far right, then less to the right, (cairns,) where the angle eases, then go back to the left on a vague ridge.
From there go up the glacier to the left, (serac risk), until the bergshrund of the Grands Charmoz, pass it as best you can to gain the terraces on the true right bank of the Charmoz-Grépon couloir.

Route 6 to 10h

From the foot of the couloir to the gap 3421m 2h

Climb to the left of this couloir for about 200m until large terraces which you follow to the left, (obvious large cairn.) Traverse leftwards at about the level of a red tower.
You come to a series of chimneys and corners to the right of a red spur. Climb this line, 4c max, including the Burgener crack, which is often verglaced.

From the gap to the summit of the Charmoz-Grépon couloir 2h

Start the ridge by turning the first pinnacle on the Nantillons side (4c, 2 pegs).
Follow the crest of the ridge, (3b, exposed,) and reach the next gap by a short and delicate down climb on the Mer de Glace side.
Bypass the third pinnacle (La Carrée) again on the Nantillons side, firstly on a large flake then by slabs to reach after a pull-up a platform under a thin pinnacle the “Bâton Wicks” (4c).
A short abseil leads to the next gap. Follow the tapered ridge for several metres to reach another abseil, which you need to pendule to reach a platform of boulders (15m). From here you can climb to the highest point (4b).
Descend by easy but bad rock to the top of the Charmoz-Grépon couloir.

From the top of the couloir to the summit of the Grépon 2 to 3h

Do not go to the lowest gap, (in the line of the couloir) : climb a corner, "the open book" (4b, 2 pegs,) which leads to the gap to the right of col Charmoz-Grépon. Go onto the Mer de Glace side, traverse for 20m then climb back up to another gap at mid height of the Mummery crack.
You reach the crack either by a short but delicate traverse, (5c, 2 pegs, steep slab) or by climbing down 4 metres and then traversing (4c, slab).
Climb the remaining 10 metres, tricky for 3m, (5b).
Go back onto the Mer de Glace side by the "Trou du Canon", climb a crack capped by an overhang, (4b,) to the left, and pass back onto Nantillons side through a slot (“letter box”.) Hand traverse the flakes on the ridge, (4c,) then follow the sharp ridge, (2 pegs high up, the start of the flake traverse is a bit committing.)
A first abseil leads to a gap from where you climb the next pinnacle (3c.) From there, abseil down the Nantilons side to a ledge which you follow to the next gap. A narrow ledge on the Nantillons side then a long stride after having gone over to Mer de Glace side, brings you to the "Vire à Bicyclette”, (cycling ledge). Follow this to its end. By another flake, hand traverse on the right, (easier than the one before,) to reach a delicate, Z shaped crack, (1 move of 4c, protectable with nuts,) on the Nantillons side., which you climb to the summit and the statue of the Virgin.

Descent to the Col des Nantillons 1h

From the summit make an abseil of 20m on the Mer de Glace side to reach the Balfour gap. From there, in two abseils of 25m, reach an obvious shoulder, from where a 30m abseil leads to a deep gap. Climb back up the little wall opposite of 3m, (3c,) without releasing the rope, which gives access to a terrace.
At the end of the terrace down climb the shoulder and ledges, leading to near the Col des Nantillons.

Return to the Start of the Route 1h
Go onto the glacier, and join the approach route near the Charmoz bergschrund, by going from left to right.

An alternative is, depending on the state of the glacier, to go to the true right side of the glacier and descend a ramp of broken rocks a long the base of the Grepon. An abseil of 25/30m, good belay, (pegs and slings,) brings you to within a few metres of the start of the route. Return to Plan d’Aiguille by the approach route.

It is also possible to abseil from the summit of the Grepon all the way to the ramp, (Recommended at the end of season or if the glacier is particularly dry.) After the first two abseils of 25m identify an ovbvious boulder at the end of a terrace (2 bolts.) From here a series of abseils, always with new bolts, leads down to the middle of the ramp. Careful 50m abseils unavoidable.

About 400m of height gain from the bergschrund to the Summit of the Grepon, however the distance along the ridge is considerable. A long route!

Crampons and 1 ice axe each, particularly for the descent of the col des Nantillons ;
Slings, nuts and friends ;
Rope : 60m advisable, 2×50 m if you take the new abseil line.