Baldwin Cirque / SE Couloir
Sunday, December 30, 2018 - 12:45pm
*italics added by forecaster with consent from reporting party*
Two skiers left before dawn up the McGee Creek drainage, headed toward the Baldwin Cirque. The goal was to ski the SE Couloir of Mt. Baldwin, hopefully dropping before the height of the day given the warming and solar.
Arriving at the morraine around 9:45a, the group was a little late. Surprisingly, they found the snow in prime condition - cold, relatively untouched by the wind. The SE Couloir was in the sun but was starting to come back into the shade. Looking around, there were no signs of instability or avalanche activity. The group noticed that the sun was warming the snow up in the apron below the couloir, but there was little if any moisture in the top of the snowpack when skinning towards the couloir. The conditions caused the skiers to relax their sense of urgency to ski the line and be out before noon, which ended up being a critical mistake.
Inside the lower section of the couloir, the snow was cold and without a sun crust on the climbers left side. The climbers right side had a slight sun crust. Something that we did notice at the time but did not put much weight to until after the fact was actual flowing water down the right hand rock wall of the gully. After climbing the lower section, the group reached some breakable crust and started to wallow. With climbing/skiing conditions deteriorating and the day dragging on, the two decided to turn around and ski back to the car. This happened at the bend in the chute where it turns climers left and heads up to the ridge. Had the group continued above this point, this would likely be an even more serious post.
About to drop in, with one skier clicked in and ready to ski and the other still without skis on, they heard a loud noise from above. Looking up, there was a river of snow coming down - only enough time for two words "oh f*ck." The two skiers tried to escape to the climbers right, but the attempt was useless. The seemingly double-overhead wave of snow hit them both, knocking the uphill skier (with skis on) forcefully into the downhill skier and carrying both down the lower section, off the rock walls multiple times, partially submerged for parts of the ride. The fall was somewhere between 400-800' and the slide likely D2/R2. Luckily, both skiers ended up mostly on top of the debris with a few bruises and missing gear. They each had one ski and no poles, but were able to ski back to the trail and walk out in the dark.
While both skiers made it out safely and unharmed, this incident was a serious reminder of the dangers that exist above when booting a steep line. It's also a reminder that even in periods of relative stability, avalanches that could easily kill a person can naturally trigger given the right confluence of loading/solar/thermal. It's still unclear whether a wind slab in the couloir broke due to warming despite being in the shade, or if snow on the south rock wall that was still in the sun broke into the couloir and started the slide. Either way, the group is lucky to be alive and well.
We debated posting this, but in the end, believe that it's best for the community to have the observation shared. We are not proud of the incident and are taking time to process what it means for our decision-making in the future.
Some addiitonal thoughts after this post that the party commented about to ESAC follow:
-The place they chose to transition was right in the middle of the gully, and they took close to half an hour to transition in this exposed place. Would they do it again, it seems like an easy choice to transition under the large rock in a place more sheltered from overhead hazard than next to this rock in the gut of the couloir.
-They saw no spindrift of any kind coming down the couloir, and noted only a couple short periods in the morning where ridgetops winds were blowing and transporting snow at all. This makes it seem highly unlikely that the natural trigger was addtional snow loading from wind.
-One person's camera was ripped from his pocket during the slide. The other person had his beacon in his pant pocket, which ended up bruising his leg and getting cracked, and then showing error message when checked later in the day. His pant pocket also got a rip in it, but the beacon was not ripped out. He said he will never again put his beacon in a pant pocket again, and will always have it strapped to his chest in the future.
-Stuff strapped to the outside of his backpack, such as his ice ax, were ripped off. This reinforced how important it is to keep important things like shovel and other rescue gear tucked safely inside. Also of note, the 2nd person got hit by the avalanche when his backpack was off, so he was without his rescue gear when he came to rest at the bottom of the slide. Fortunately he didn't need it to perform a rescue.
-The reporting party mentioned that he skied the same line the year before in similar warming conditions, reaching the top, but later than they had planned. He couldn't help wonder if "getting away with it" last year made them more willing to push past their turn-around time this year of 11am.
-The second less-experienced party did mention that he was likely effected by the expert halo heuristic trap, knowing that his partner had atleast twice as many back country days under his belt.
-Forecaster thoughts: While not certain, it seems highly likely that this was a wind slab avalanche that was triggered by solar radiation warming the sourounding rocks and slope during the height of the day from the southerly sunny upper slopes above the couloir. The snowpack on that face was surely thin, making it quite possible that weak faceted snow existed underneath the recently deposited wind slab.. We greatly appreciate those involved for submitting this report. It's an invaluable account that we can all learn something from.
*The 2 attached photos were taken at 10am, showing the slope exposure to sunshine at that time. At the time of the slide the slopes lookers left of the couloir were in the shade.