Accident: Butler Basin

Observer Name
UAC Staff / White
Observation Date
Saturday, January 28, 2023
Avalanche Date
Saturday, January 28, 2023
Salt Lake » Big Cottonwood Canyon » Butler Fork » Butler Basin
Location Name or Route
Butler Fork
Slope Angle
Trigger: additional info
Unintentionally Triggered
Avalanche Type
Soft Slab
Avalanche Problem
Wind Drifted Snow
Weak Layer
Density Change
Buried - Partly
Accident and Rescue Summary
With permission and from Mark White's Blog : "Today we headed up Butler Fork thinking that we would stay out of the wind and ski a sheltered NE facing bowl at around 9,000ft. We realized the snow was denser than expected and slightly inverted on our hike in but we stayed out of the wind and never felt any slabby snow. This bowl is steep at the top, 38 plus degrees, then mellows out rapidly in the middle. We ascended in the steep trees on skiers right side, did a ski cut that only produced sluffing and skied the bowl with no obvious instabilities. We proceeded to hike up again but this time went up about 10 feet higher, still on the edge of the trees. My partner was about 10 feet in front of me and stomped out a flat spot to take his skins off, next thing we know the bowl is fracturing 50ft above us. My partner was on the edge of the slide and just got pushed 2 feet. I was in the middle, got pushed into a stand of trees and got buried to the top of my chest. I also heard and felt my hamstring pop. I was still in hiking mode with toes locked in and skins on with my legs all twisted up. It required my partner to dig me out and release my skis from my feet. A few minutes after I was out we heard a pop and the middle of the bowl pulled out remotely. The first slide was 100ft wide, 18 inches at the deepest point. The next slide extended the crown to 250ft and ran to where the slope flattened out. I doubt we would’ve triggered a slide if we would have stayed lower out of the windslab. The windslab wasn’t obvious but it only makes sense in retrospect. There’s a massive cornice at the top and while the wind wasn’t out of hand it was still loading the slope right below the cornice with denser snow. Sometimes the line between triggering a slide and not is thin but it sucks to be on the wrong side of that line. Just glad I had a good partner with me and can ski on one leg fairly efficiently. Mistakes were definitely made but we live and hopefully learn from them."