Risk 2 in the avalanche bulletin is a moderate risk of skier triggered avalanches. It is generally taken to be a green light for ski tourers and so it was on Monday 1st December 2025. Good weather with the zero isotherm above 2000 meters in the afternoon.
A 50 year old skier was caught by a small slide above the refuge de l’Oule in the Belledonne mountain range. A popular sector for ski tourers with its large north-west valley accessing multiple cols and summits. The area around the refuge is also avalanche prone and has been the location of a number of dramas in the past, even at risk 2. The skier was carried over cliffs and suffered chest, back and shoulder injuries. We don't have the exact location but it was at approximately 2200 m on a NW facing slope.
The avalanche bulletin noted "excellent snow conditons" in the mountain range for the time of year with a "small layer of fresh snow, around 15cm, in sheltered areas, windblown near ridges and cols." The wind was given as 20 km/h from the north overnight.
Ptit Xav writing on skitour.fr said that he noted wind transport at altitude from the trail head. Another group told them they saw a purge off the steep slopes below the refuge. He considered the conditions much more dangerous than Risk 2 with a lot of wind and snow transport. He saw the other group trigger a slab above the refuge and warned "the terrain is mined, be careful". Another group was further south in the Belledonne in the lac du Crop sector. At the entrance to a narrow passage on the steep part of the couloir they were skiing, at 2300m altitude, they noticed instabilities but were not worried as there wasn't much snow depth but they decided to stop there. However as they were preparing to ski down they triggered a slab from above and one of the group was swept down slope, losing a ski but escaping without injury.
Another group noted a weak layer at 80cm from the surface in a snow pit they dug but the avalanches above seem to have been on the recent wind blown snowfall. This group photographed a large slab which had broken around rocks. This is inline with the avalanche bulletin that noted that slabs could be triggered where the snow pack is thinner.
https://www.data-avalanche.org/romansns-test/?1764596514393
Did the forecasters underestimate the risk?
The ski resorts, which are an important source of information, have only just started opening so data from the ground is lacking. The bulletin noted a persistent weak layer above 2200 meters on "rare, shaded slopes in a wide north sector beneath the snowfall between Sunday 23rd and Wednesay 26th November". Exactly as we see in the snowpit in the link above. These slabs could be skier triggered at the edge of the accumulation zone - the snow pack is thinner here so it is easier to trigger the weak layer. Additionally there are a few "new slabs, powdery in appearance and hard to identify near ridges exposed to the moderate north to north-east wind form by the new snowfall."
The skiers on the ground seemed surprised by the avalanche activity but it appears to correspond to the small slabs sensitive to skier triggering mentioned in the bulletin and that even these small slabs can have consequences above cliffs or in narrow couloirs. In both of the incidents described above the skier remained on the surface whereas at risk 3 there would be a greater risk of being buried with all that entails.
Anyway an interesting lesson for the start of the season and as Xav noted, conditions on the ground can differ from the forecast and there is no harm in making a U-turn, as his group did in those circumstances.