Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain on Friday
Weather Forecast
Wednesday: Starting off clear and cold but clouds should develop around noon. Afternoon temperatures will rise. The region should stay dry until Wednesday night. Thursday: Light snowfall with 5 cm expected (maybe 10 cm right on the coast). Freezing levels around 800 m. Friday: Models are in disagreement, but amounts of around 15 cm new snow, strong southwest winds and freezing levels spiking to 1400 m is the most likely scenario at this time.
Avalanche Summary
No new avalanches have been reported in this region recently.
Snowpack Summary
Generally light snowfall has buried an assortment of old snow surfaces including crusts, old wind slabs, surface hoar and surface facets. The crusts have formed on all aspects at lower elevations and on steep solar aspects higher up. Old wind slabs were on a variety of aspects behind exposed terrain features. The surface hoar (5-10mm) was most prominent at and above the recent cloud associated with inversion conditions. Friday's moist snowfall may have destroyed this surface hoar in many places. Surface facets have grown particularly on northern aspects where colder temperatures have persisted. In general the snowpack is now well bonded in most locations. A mid-pack layer of concern is a rain crust (buried on Feb 1st) now down 10-40 cm, which exists up to about 2000 m. This may have potential to become reactive with additional snow load in areas where additional crusts do not lie above it, such as north aspects at treeline. Lower layers include a mid-January crust (down 50-100 cm), and a mid-December crust (down up to 200 cm); these now only present concerns in shallow snowpack areas. The average treeline snowpack depth at is around 240cm.
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.