Expect avalanche activity to increase as the recent new snow settles in the coming days.
Confidence
Low - Timing, track, or intensity of incoming weather system is uncertain on Wednesday
Weather Forecast
TUESDAY: Mainly cloudy with isolated flurries, wind light to moderate east, alpine temperature -10 WEDNESDAY: Mix of sun and cloud, wind light north, alpine temperatures -12 THURSDAY: Mix of sun cloud and isolated flurries, wind light to moderate north, alpine temperature 10
Avalanche Summary
Recent reports indicate natural and explosive triggered avalanches to size 2 and loose snow avalanches to size 1 in steep terrain. Expect to see avalanche activity increase as the new snow accumulates and settles in the coming days.
Snowpack Summary
15-30cm of new snow accumulating Friday through Sunday evening sits on a wide variety of old surfaces including large surface hoar (weak, feather-like crystals), hard crusts formed by sun or wind, and sugary facets. As the snow load builds and slab properties develop, it will be important to monitor how the new snow is bonding to the old surfaces. Most concerning would be areas that have surface hoar sitting on top of a hard crust. A crust which was formed by rain in late November is a major feature in the snowpack and is down approximately 50-80cm at tree line elevations. Snowpack tests suggest the snow above is currently bonding well to it. Snowpack depth decreases rapidly below tree line. Look out for early season hazards such as rocks, stumps, and open creeks.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.