A long day with a lot of traversing, but worth it for one of the most stunning lines in the area. It is accessible from the Serre Chevalier valley or the Névache valley, the following description is from the Serre Chevalier valley.
From the parking at Le Pont de l’Alpe, head over the bridge and head east then north on the path to the village of L’alpe du Lauzet (some times you can only see the roof’s of the buildings in winter). From there climb east up the big steep slope, at the top of this head north into the torrent du rif Valley.
1) to stay high on the right side of the valley and traverse it, steep in places but less distance, can be a pain if icy.
2) Drop in to the Valley bottom and traverse there, it’s longer but flatter there is a climb at the end.
From the 2603M spot hight make your way up and behind some rocks and in to the couloir. From here climb to the top. On my GPX we didn’t go to the top as there was a very big cornice at the top which we didn't fancy being under.
Ski back down the couloir and then back in to the long valley. It’s probably more fun to ski down in to the valley floor and maybe have to do a bit of poling at the end. Or you can traverse the long way across steep slopes. Ether way at the end descend to the village and from there continue down to the parking.