Regions
Northwest Coastal.
Confidence
Fair - Forecast snowfall amounts are uncertain on Saturday
Weather Forecast
Strong northeast outflow winds are expected to continue until at least Saturday afternoon. The temperature is expected to rise to about -12.0 in the alpine by Saturday morning. Blowing snow overnight should accumulate to about 15 cm by Saturday morning. Sometime Saturday afternoon or evening, the winds should shift to the southwest and become strong and gusty. The snowfall is expected to increase overnight, bringing an additional 20 cm by Sunday morning. Precipitation should decrease during the day Sunday, followed by another pulse of warmer wet weather on Monday.
Avalanche Summary
Some natural and cornice triggered avalanches up to size 2.5 have been reported from slopes that were loaded by the recent strong NE winds.
Snowpack Summary
The deep snowpack is considered to be well settled with no persistent layers of concern. Some areas have about 20 cm of dry cold snow above the old storm snow that ended about January 8th. Windslabs that have developed due to strong NE outflow winds have not bonded to this layer. Some areas have developed surface hoar or surface facetting on sheltered slopes in the alpine and at treeline.
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.