Regions
Northwest Inland.
Confidence
Fair - Due to limited field observations
Weather Forecast
Saturday night and Sunday: An upper ridge remains over the coast bringing dry conditions and light W winds until a front reaches the coast in the evening Sunday. Monday: Only traces of precipitations associated with the weak front are expected to reach inland and winds should be felt moderate to strong from the Southwest. Freezing levels are expected to remain at the surface but temperatures to warm up slightly with the arrival of the front. Tuesday: Temperatures around -4 C, no precipitation, light SE winds.
Avalanche Summary
No recent avalanches have been reported.
Snowpack Summary
A few cm fell since yesterday with relatively light winds from the NW. As a general overview, a shallow snowpack (about 1m deep) exists, with facets that have continued to develop with this week's cool arctic air. Strong winds have scoured some SE aspects in the alpine to ground. Wind slabs exist in many wind-exposed areas, however their distribution is quite variable and some areas have no wind-effect at all. Below treeline, very loose cold snow is sluffing easily from steep terrain and early season hazards like exposed stumps are still to watch for. Professionals are still mindful of a facet/crust layer near the base of the snowpack. Although triggering it has become unlikely, it may be possible from a thin-spot trigger point or with a very heavy load (e.g. cornice fall).
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.