Avalanche: Y Coulior

Observer Name
Matt Asay/Ryan Hobson
Observation Date
Friday, April 12, 2019
Avalanche Date
Friday, April 12, 2019
Region
Salt Lake » Little Cottonwood Canyon » Y Coulior
Location Name or Route
Y Couloir
Elevation
7,500'
Aspect
North
Trigger
Skier
Depth
15"
Carried
1
Comments
We skied Maybird Couloir late in the day yesterday, and hadn't seen the slightest sign of instability. We figured it wouldn't be terribly dissimilar across the canyon, even with the opposite (north-facing) aspect. By 7700 feet or so the snow had turned to ice and as we approach 8000 feet we decided to bail early, not wanting to skid down 1500 feet of ice. It had been snowing reasonably hard as we climbed, but it wasn't layering the ice with anything more than an inch or two. Or so it seemed.
We proceeded down with only the most minor of sloughing of the new snow. I skied 50-100 feet below my partner to wait for him. We had radios but wanted to keep within eyesight. We reached a point at roughly 7,500 feet where the snow was soft and fun and as I turned to take a picture of my partner skiing down, a wall of snow hit me and knocked me off my feet. My partner also got nailed ("a shockingly hard hit") but was angled in such a way that he absorbed the initial shock and skied to the side. He couldn't believe how much snow kept coming, given that what we were booting up for the last few hundred feet had been ice and we assumed it continued above us.
At this point I had been carried by the snow 800-900 feet out of sight. My partner put his beacon in search mode and started down, calling me on the radio. (We always carry radios.) I was trying to self-arrest but had foolishly left my whippets in the car and couldn't get my elbows down into the slope or anything to stop me. Had we been in Y-Not with cliffs, it almost certainly would have been much worse. Fortunately, the river of snow eventually spit me out to the left, maybe at about 6600 feet? My partner met me a minute or two later. All of my gear was intact (ironically, I was still holding the phone I'd pulled out to take a picture).
In terms of learnings, we felt like we had managed risk reasonably well, having observed conditions the evening before and as we climbed. THAT SAID, the snow started coming down pretty hard while we were climbing. Our best guess is that it was new snow piling on yesterday's load that triggered the release. We weren't really noticing how fast it was coming down, but that seems like the clearest explanation for where all that snow came from. In the same situation again, we'd turn around when in steep terrain when the snow starts to fall in earnest.
Sorry, no pics. We were both a little busy.