Avalanche hazard will remain elevated as the storm continues, especially in areas with accumulations of 20 cm or more.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
TUESDAY NIGHT: Scattered flurries with accumulations between 5-10 cm. Alpine temperature low -10C. Light northeast winds. WEDNESDAY: Mix of sun and cloud. Alpine temperature reaching -5C with light west winds. Freezing level at 1300m. THURSDAY: Mainly cloudy. Dry. Slightly colder with high temperature of -8C. Light west winds at ridgetops.FRIDAY: Mainly cloudy. Dry. Alpine temperature reaching -4C. Light south west winds at ridgetops.
Avalanche Summary
Small and isolated (size 1) wind slab avalanches were naturally triggered Monday on steep alpine features. With this new round of precipitations and wind, storm and wind slabs are likely to be reactive on heavily wind exposed terrain at treeline and alpine, where small loose dry avalanches are likely on steep terrain.
Snowpack Summary
15-20 cm of storm snow has buried hard wind slabs in the alpine and open areas at treeline on various aspects due to variable past winds. This new snow also sits on sun crusts on south facing slopes and on isolated surface hoar crystal on north-facing slopes. The mid-snowpack consists of sugary faceted grains (facets) of different hardness. Two older layers of surface hoar are now down 55-80 and down 95-150 around 1600-1900m. The lower snowpack is generally well-settled.
Problems
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.