Southern San Juan

Avalanche

Chris Bilbrey Jeff Davis · Jan 4, 2022 · Southern San Juan

Weather

Cold day with moderate westerly winds. Winds were moving lots of snow onto northeast, east and southeast-facing slopes above treeline. Shallow, fresh slabs starting to form near treeline becoming thicker and stiffer the higher we climbed.

Snowpack

We found a supportable upper snowpack at all elevations. Soft remnants of snow that fell last week is found on the surface of many wind-sheltered slopes. Southerly-facing terrain has a thin, breakable crust and upper elevation slopes harbor fresh wind-drifted slabs. December snowfall accounts for the majority of total snow depth making it more difficult to detect the presence of old, faceted snow at the ground. The only direct feedback from the snowpack were 2 separate collapses on wind-loaded slopes near treeline. They were localized, but occurred on slopes where old facets and depth hoar linger below a 120 cm or deeper slab. Our snowpit and stability test identified a reactive storm layer in the top 50 cm's of the snowpack, and old facets at the ground continue to fail albeit with hard force. Lots of fat, pillowy slopes exist in the alpine and cornices grew significantly over the last two weeks. With newly formed drifts, reactive layers in the upper snowpack, and weak facets at the ground trying to find equilibrium under a stout slab, we continue to give steep, northerly-facing slopes the time they need and a wide berth. Slopes without old snow, the snowpack is fairly homogenous and continues to offer safer riding options.

Avalanche

Observed several old crowns on northeast and east-facing slopes above treeline. Crowns were mostly filled in making it difficult to estimate size.