Skier controlled-ish in Montana Bowl

Carte pour le rapport du Réseau d'information en montagne: Skier controlled-ish in Montana Bowl

Information

Date/heure de l'avalanche
dimanche 4 décembre 2022 à 22 h 00
Estimation de l'heure d’occurrence de l’avalanche
> 12 à 24 heures
Nombre d'avalanches dans ce rapport
1
Taille de l’avalanche
2
Épaisseur de la plaque
70cm
Largeur de la plaque
70m
Longueur d'écoulement de l'avalanche
200m
Caractère de l'avalanche
  • Plaque à vent
Type d'élément déclencheur
Skieur
Sous-type d'élément déclencheur
Intentionnel
Versant de la zone de départ
  • SO
Bande d'altitude de la zone de départ
  • Alpin
Altitude de la zone de départ
2 250m
Inclinaison de la zone de départ
40°
Altitude de la zone de dépôt
2 100m
Date d'ensevelissement de la couche fragile
dimanche 20 novembre 2022
Type de cristaux de la couche fragile
  • Givre de surface et grains à faces planes
Croûte près d'une couche fragile
Non
Exposition au vent
Pente chargée latéralement
Couverture forestière
Pente dégagée

Commentaires

Ski cut a decent avalanche in Montana Bowl around 2pm. I got some loose, wet snow running down from the trees when approaching the col. From the col I could see the gut of the run had almost no snow in it, ground was still showing in several places. It had either been stripped in previous wind events or had cycled naturally already sometime in the past, but I strongly suspect it was wind. The options were either hike back out or do some more cutting and see if I could rinse more snow through the gut to clean it out and ski down. I cut a little more and it popped on the thin-to-thick interface where the wind slab ramped up under the rocks at ridge top. Pretty classic trigger point, but it happened right at the end of the cut when I was moving pretty slow, and broke about a metre above me, so I still had to ski off some moving chunks. Wasn't the greatest ski cut of all time. Crown top was about 15 to 20 metres wide but propagated quite a bit wider lower down in the bowl, to around 70 metres, just judging by eye. Because it went more or less to ground in the middle of it I'm not totally sure what layer-date reacted. The gut cracked 10 to 15 cms deep (since that's all the snow that was in there), but along the flanks where the windslab was deeper the crown was about 70 cms. Ran more or less full path, it stopped just a little short of the bottom of the bowl. I skied the bed surface after and checked out the edges. Another post is calling it a size 3, I personally think that's an overestimation, but either way it's still not something you would have wanted to be in. It was a marginal ski cut, and the right decision would have been to hike back up and out, or to have not been there in the first place, which was also pretty obvious. It's spicy in the alpine and still early season, don't be me.