Skier controlled-ish in Montana Bowl

Map for Mountain Information Network report: Skier controlled-ish in Montana Bowl

Information

Avalanche date/time
Sunday, December 4, 2022 at 22:00
Estimated occurrence time of avalanche
From 12 to 24 hours ago
Number of avalanches in this report
1
The size of avalanche
2
Slab thickness
70cm
Slab width
70m
Run length
200m
Avalanche Character
  • Wind slab
Trigger type
Skier
Trigger subtype
Intentional
Start zone aspect
  • SW
Start zone elevation band
  • Alpine
Start zone elevation
2,250m
Start zone incline
40°
Runout zone elevation
2,100m
Weak layer burial date
Sunday, November 20, 2022
Weak layer crystal type
  • Surface hoar and facets
Crust near weak layer
No
Wind exposure
Cross-loaded slope
Vegetation cover
Open slope

Comments

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.