Northern San Juan
AvalancheAnn Mellick · Dec 22, 2020 · Northern San Juan
Weather
Clear to start with increasing clouds ahead of the incoming storm. Strong and gusty southwest winds.
Snowpack
Strong winds were the headline today with persistent SW winds causing a fair amount of blowing and drifting snow. Winds also kept the snow surface much cooler at all elevations today, despite the mild air temperatures. Warm temperatures yesterday (12/21) helped settle recent storm snow. It also formed a new surface crust on sunny slopes (unsure if this is true in the alpine). Well developed surface hoar noted below treeline today which will need to be monitored once buried by the next storm- especially where it sits on crusts on sunny slopes. This layer did not burn off today. The snow structure on sunny slopes is now very weak as well, with large faceted grains (25 cm) sandwiched between a basal and surface crust, with surface hoar on top- weak! I observed only localized cracking/collapsing near my skis on very steep north and westerly slopes- much less widespread and touchy than just after the last loading event (12/18). However, the snow structure seems to be getting weaker and the formerly firm midpack seems to be breaking down and faceting with time.
Avalanche
A fair amount of wet loos activity (D1) with warming on Dec 21. All originated from steep rocky terrain.