Northern San Juan
AvalancheKaylee Walden · Dec 3, 2018 · Northern San Juan
Weather
The weather had just cleared after the initial storm; it was lightly snowing, partly cloudy and essentially no wind. We descended the upper portion of the line cautiously, noting some wind-loading from the west over the ridge. We had reached the final (sometimes called the "Snodgrass" pitch) without issue, albeit a bit of whumphing on the ridgeline. I was waiting in the trees with eyes on my partner while he skied the pitch. He was able to move out of the path of the slab immediately after it released.
Snowpack
The storm layer collapsed on a layer of surface hoar that had formed on top of the old snowpack in a sunny, thin, E/SE-facing aspect.
Avalanche
My partner made a turn out onto a steep (approx 38-degree) pitch with few trees, which set loose the storm slab. It propagated about 30-35 feet wide. Crown was 10"-24" inches deep, and ran for about 150'. The slab was very low-density and slow-moving, and my partner was able to easily get out of the way. We had given the party ahead of us plenty of time to exit the line before we began skiing, and the slab stopped before continuing into the gully below. We had a little cracking but no other issues for the rest of the ski down. No injuries, no burial.