Using the lift at Pelvoux helps you to gain height quickly.
Park at the Pelvoux ski station and buy a rando pass, giving you a one-way ticket to the top of the resort (2 chairlifts). At the top of the first lift take the chairlift on the right. At the top of the second lift, with skins on, head away from it up a gentle slope (west) that kicks up just before the Croix du Chastellet. From the cross follow the ridge. After a couple of hundred metres drop off the ridge to the left into a bowl. (It is possible to continue over the ridge.) From the bowl traverse up and to the right (north-west) and rejoin the end of the ridge. There is a sign here in summer, but this may be buried under the snow. From this point traverse right (north) until at around 2600m you will see the ridgeline with the Rouya peak. Head towards the ridge. Below the summit of the Rouya at around 2700m you will find the entrance to the couloir. (There are several so make sure it’s the right one.)
The first 20 metres are steep. (Having a rope may help, or axe depending on conditions.) Once down the first bit the route bears right and you should see it narrow between two rock faces (see photo). Follow the obvious line down and into the Ravin de l’Alpet which comes out in Ailefroide. On the left (north) side of the valley the footpath runs back towards the village. Follow it then ski across the campsite and back on to the road D994. This should be covered with snow; ski down it to just before the road tunnel. A path going left (SE) leads you back to Pelvoux ski centre parking. If there isn’t enough snow, you must walk or hitch from the tunnel.