Regions
Northwest Coastal.
Heavy loading from snow, wind, and rain is likely resulting in natural avalanche activity.
Confidence
Fair - Due to the number of field observations
Weather Forecast
On Wednesday expect another 5-15 mm of rain (or cm of snow) as freezing levels to drop as low as 1500 m in the southern part of the region or lower up north, and alpine winds continue to blow strong from the southeast. Thursday is looking mostly dry as freesing levels hover around the 1000-1500 m mark and alpine winds ease off throughout the day. A bit more snow could arrive on Friday with up to 10 cm in some areas accompanies by moderate to strong southwesterly alpine winds and freezing levels dropping below 1000 m.
Avalanche Summary
Reports from Monday include several explosive-triggered storm and wind slab avalanche up to Size 2.5 at all elevations and on all aspects. The slabs were no deeper than 35 cm and failed on old facets under recent storm snow, or right on the ground in shallow snowpack areas below treeline.
Snowpack Summary
Heavy rain is saturating the upper snowpack and resulting in wet, loose, and cohesionless surface snow as high as alpine elevations in the southern part of the region. While in the alpine and as low as treeline elevations further north wet snow and wind has formed new storm slabs and is overloading previous weaknesses buried within the snowpack, such as the mid-November crust-facet layer.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.