Regions
Northwest Coastal.
Conservative terrain selection is critical. Don't let the lull before the next storm lure you into a more aggressive approach. Dangerous avalanche conditions still exist.
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
A series of Pacific frontal systems will continue to dominate the weather pattern and hit the coastal regions throughout the forecast period. Saturday/Saturday night: Snow amounts 5-10 cm during the day with near 15 cm overnight. Alpine temperatures high of -2.0. Light-moderate SE ridgetop winds and freezing levels rising to 800 m. Sunday: Snow amounts near 10 cm. Alpine temperatures near -4.0. Moderate-strong SE ridgetop winds and freezing levels 500 m.Monday: Moderate snow amounts accompanied by light SW winds expected.
Avalanche Summary
No new recent observations. Numerous size 2 natural storm slab avalanches were observed on Wednesday. As well, a few size 2.5 storm slab avalanches were remotely triggered from up to 200m away. Due to the nature of the buried weak interface and forecast weather, ongoing storm slab activity will likely continue.
Snowpack Summary
Recently, the region has received 60cm or more of new snow. The recent snowfall overlies a variety of old surfaces which consist of weak surface facets, surface hoar (more predominant at treeline and below treeline elevations), a scoured crust, wind press, or any combination of these. Reports from the field indicate a very poor bond between the new snow and these old surfaces with accounts of whumphing and easy, sudden planar snowpack tests at all elevation bands. Strong winds and slight warming have added cohesion to the new storm slab, and have shifted the new snow into deeper, and potentially destructive wind slabs in exposed terrain.The mid and lower snowpack are generally strong and well-settled. Basal facets and depth hoar are likely to exist in some parts of the region, but triggering has become unlikely.
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.