Incident report White Pine 2/24/23. 10:30 AM

One caught and carried, none buried, none injured

Party of six after skiing Red Baldy back into WP, re-ascended the fast-becoming well-worn skin track up Red Baldy. Stopped near the top to assess the due north facing aspect. Discussion of line, escape path ensued. Skier 1 cross cut the slope which yielded a superficial slough that was quite thin, but ran a good distance down the slope. Further discussion followed, and he skied to a stable point to the skiers right of the planned descent to stand watch. Skier 2 followed the cross cut right, then cross cut left across the slope, yielding similar mild results. He turned right into the descent. The best exit was left. There was small slough with each turn, which seemed manageable. Sloughs were now on both sides, but as he came back right on the third or fifth turn, the slough on the right had gained momentum and mass. He was knocked from his feet, and lost one ski pretty early. The party above identified the danger and tracked the skier visually.

Skier two was swimming and maintained on-top, but the slide successively gained momentum. He felt he was being propelled by the one remaining ski, and at one point was spun prone, face down in the snow. He felt he was hit by more snow which popped him supine and back to more swimming. As the pitch mellowed, the rate of advance slowed, but he was surprised by just how long the snow kept moving, and he kept swimming. When it stopped moving he had both arms and his chest above the snow. The remainder of the party above were tracking visually and had had time to switch to search at that point. Skier one descended the slide bed to skier two, who was unhurt.

Lessons:

Forecast was for good stability especially north facing, but slope angle still matters. We were erroneously encouraged by stability observed via multiple tracks on lines with similar aspect, pitch, and altitude.

None of this broke deep (a so-called “slough-alanche”). There was no crown. It was all “superficial slough”. But over a great enough distance, it can develop a ton of mass and energy.

I (skier 2) did not take the “slough” seriously enough. As I saw it on successive turns, I should have executed the exit left, rather than turning back into what I thought was harmless, but was in fact a growing mass of moving snow. The pile where I came to a rest was very deep, as it represented the accumulated surface snow of that entire slope.

While we discussed exit, etc, we perhaps should have discussed slough more before the start.

While the swimming may have helped keep me on top, I felt I was at the mercy of my ski with regards to how I was positioned in the snow.