Regions
Northwest Coastal.
Confidence
Fair - Freezing levels are uncertain on Tuesday
Weather Forecast
Snow and wind from the southwest is expected to accumulate 15-20 cm by Sunday morning. A weak ridge of high pressure will cause some broken skies and generally drier conditions during the day on Sunday. Snow should begin again Sunday evening combined with gusting westerly winds, bringing about 20 cm by Monday morning. Flurries are forecast for Monday, becoming heavy snowfall with rapid warming on Monday night and continuing heavy snowfall on Tuesday.
Avalanche Summary
Reports of widespread whumpfing at treeline and above on hard windslabs. Skier accidental reported to size 2.0 from a south aspect on a convex roll. Natural activity reported from the Bear Pass area in the highway corridor.
Snowpack Summary
The deep snowpack is considered to be well settled with no persistent layers of concern. There is now 20-30 cm of dry cold snow above windslabs that have developed due to strong NE outflow winds which have not bonded to the January 8th surface. These pockets of hard windslab can be triggered by light loads such as a single skier or rider. Some areas have developed surface hoar or surface facetting on sheltered slopes in the alpine and at treeline, that are now getting buried by new snow and shifting winds.
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.
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.