Regions
Northwest Coastal.
Confidence
Poor - Timing, track, or intensity of incoming weather is uncertain for the entire period
Weather Forecast
Saturday: Moderate SW winds, changing to strong to extreme NW. Alpine temperature near -6. 5 cm snow.Sunday: Strong to extreme W to NW winds. Alpine temperature near -8. 10-20 cm snow.Monday: Light W wind. Alpine temperature near -13. Very light snow.
Avalanche Summary
Small soft slabs and loose dry avalanches have been failing naturally and with skier traffic. A size 3 avalanche failed naturally in very steep terrain on Thursday.
Snowpack Summary
Variable amounts of new snow are building up over a medley of surfaces including hard and soft wind slabs, scoured slopes, blue ice, thin melt-freeze crusts and surface hoar. Winds are shifting snow into slabs in the lee of terrain breaks such as ridges and ribs. Two persistent weaknesses (comprising surface hoar and facets) buried in the upper snowpack recently gave moderate to hard, sudden results in snowpack tests. The mid and lower snowpack is generally well settled and strong, although basal facets remain a concern in the north of the region.
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.