Southern San Juan
AvalancheChris Bilbrey Ethan Greene · Feb 9, 2023 · Southern San Juan
Weather
Cold and sunny. Strong north wind in the morning produced long-running snow plumes off summits and ridgelines above the treeline. The wind relaxed mid-morning. No evidence of fresh snow from last night's storm.
Snowpack
The snowpack remains status quo till a moderate or significant snow load is added to the snowpack. Strong winds in the morning were moving snow at upper elevations, but it was mostly sublimating back into the atmosphere versus depositing onto leeward slopes. While the wind pressed and stiffened the snow surface on northerly alpine slopes, it was not of the damaging flavor to strip snow cover from those same slopes. We found a thin surface wind skin on the south and southeast-facing slopes as we approached the treeline. This capped a weak 6 to 8-inch layer of near-surface facets (4F-). Our snowpit on a north-northwest aspect at 11,400 feet yielded stubborn results in faceted snow one to two feet below the surface. These layers produced either resistant planar failures or no results in tests. The most concerning layer to monitor is an 8-inch thick layer of weak faceted snow grains (4F-, 0.5-1 mm) sitting below a thin but stiff wind layer near the surface. This sits below the snow that fell on February 6. We observed sudden collapse failures in this layer with 10 to 12 taps, but currently lack enough volume above to be a concern at present. This setup is likely to rear its head once we return to an active weather pattern. Faceting of the upper snowpack is occurring at all elevations but is developing at a faster rate near and below the treeline.
Avalanche
No evidence of recent activity.