Accident: Little Superior

Observation Date
Sunday, February 22, 2015
Occurrence Date
Sunday, February 22, 2015

Region:

Location Name or Route
Little Superior Buttress
Elevation
10000
Aspect
South
Slope Angle
38
Trigger
Skier
Trigger: additional info
Unintentionally Triggered
Avalanche Type
Soft Slab
Avalanche Problem
Storm Slab
Width
150
Vertical
1250
Carried
1
Accident and Rescue Summary

I was skiing alone, coming back into Little Cottonwood Canyon from Cardiac Bowl after a long and very enjoyable morning of skiing mostly north and some east facing classic Wasatch powder.  I gained the ridgeline at the Little Superior Buttress, and decided to make my descent from just above it.  As I removed my skins up on the ridge, I examined the slope below. The initial portion of the run dropped about 100 feet south east facing before opening up into a broader bowl above a rock band. My intention was to make my way skiers left over to the frequently skied fin that drops from just below the buttress.
 As I gained the more south facing open bowl above the rock band, I noticed a large number of roller balls and debris coming down from above.  The next thing I knew, I was in the middle of a large wet slab avalanche.  I suppose the release knocked me down, but at first it seemed like the slab was moving slowly. it started gaining speed as it carried me towards a funnel through the rock band.  Unfortunately I was on my back with my legs and skis above me. I was unable to move to right myself and  I realized I was going over the rock band, headfirst.  The snow was so dense that I easily floated on top.  It was like riding a 2 foot thick churning carpet of roller balls and slush. I believe it protected me from the rocks as I went backwards over the probably 20' rock band.
It certainly cushioned the blow as I came down on the slope below.  Once over the rock band, the slide continued to gain speed.  I had only one ski and one pole still with me, but I managed to get an edge into the sliding snow.  I fought hard with the remaining pole and my free arm to get off of the slide to skier's left, just before it poured over the choke of a second and slightly taller rock band. For what seemed like a really long time, more than a minute for sure, the wet slide just kept pouring down from above and through the choke.
With the slide over, I waited for the adrenaline rush to subside somewhat and determined that I didn't have any serious injuries.  I dialed 911 to alert Alta Central about the slide and that nobody had been buried in it.  As I down climbed the rock band, kicking toeholds into the remaining snow, I punched through a few places to reveal a virtual waterfall- 3-4" of running water below the snow surface.
Another  200 feet or so below, the slide had come to a stop in a broad tongue of debris 2-3 feet deep.  My lost pole and ski were easily retrieved from their final resting places atop the debris pile.  Making my way down to them, the bed surface was a moistened, but still bulletproof sun crust- completely scoured of the weekend's new snow.  It wasn't until the low angle apron just above the road that I ever noted the snow surface to be getting damp and manky.

Forecaster Note: It's unknown if this was a wet loose sluff, or perhaps a slab.  So we've classified it as a Storm Snow slide.

Comments
I think the cause of the slide was the days strong sun heating up south facing rocks buried beneath the new snow. The running water I found under the snowpack on my way down after the slide, suggests to me that the slab was heating up and getting wet from below. A number of human factors played into the poor decision-making that led to my getting caught in this slide. First and foremost, after a glorious morning of skiing what seemed like very stable north facing slopes, I was in a state of elation and exhaustion as I started down the south facing. With the return of more winter like temperatures, I was not as concerned with the wet slide potential. On top of that, I was running late and in a hurry to get back to Snowbird. I dropped in to the slope like a victory lap. The conditions on the other side had made me complacent, and I made no formal assessment of the snowpack, despite the change in aspect. Lastly, a vastly less exposed route could have been taken, but I didn't want to ski back down around behind the buttress and instead chose the line above the rock band.
Comments

I doctored it to show where I got swept and where I managed to get off it. I think a whole lot of snow came down from the rocky face below the Buttress.

Coordinates