This a really nice couloir of the west face of the Tête de la Cassille, it’s not the more well known west couloir it’s just before that and is a little shorter and easier.
From the parking at Le Pont de l’Alpe, follow the footpath to the hamlet of L’Alpe du Lauzet at 1951m. Leave the hamlet and head NE up a steep angled slope through some big boulders, at the top of the slope as the angle eases start to traverse north under the west face of the Tête de la Cassille. As you traverse you will come to the first obvious couloir on your right. It’s quite a wide couloir and seems to stop at the top by a rock band. Climb the couloir and at the top there is a ramp that heads left. Follow the ramp, it narrows as it goes it up. Depending on snow you can sometimes pick a line up to the ridge, finish on the ridge or where the snow runs out.
Descent. Ski back down the couloir. Once you exit the couloir you need to think about traversing back to the south. It is tempting to ski all the way to the valley floor especially in good snow, but beware if you drop to low you can have a lot of poling to get back on to the line to descend. Head back to the flatter areas about the slope with boulders on it. Ski this past the hamlet and then back down to the parking.