Regions
Northwest Coastal.
It will continue to look and feel a lot like winter Saturday. Approach the mountains as if the calendar says January, not April.
Weather Forecast
A ridge building to the south is expected to steer the jet stream into the northwest coast through the weekend. Freezing levels should remain relatively low through Sunday and a fair amount of precipitation is expected through the weekend. SATURDAY: Overcast skies, freezing level at 1500 m, 5 to 15 cm of snow, strong south wind. SUNDAY: Overcast skies, freezing level beginning around 1500 m, climbing to 2000 m throughout the day, 5 to 10 cm of snow, strong south wind. MONDAY: Overcast skies, freezing level holding around 2500 m, scattered rain/snow showers/flurries, strong to extreme south wind.
Avalanche Summary
No new observations to report from Thursday. On Wednesday loose wet avalanches were reportedly running naturally to size 1 on north through west facing terrain between 1300 and 1600 m. On Tuesday loose wet/"moist" avalanches to size 2 were observed from steep rocky terrain.
Snowpack Summary
5 to 25 cm of new storm snow has fallen at higher elevations in the last 72 hours. The wind has primarily been out of the south during the storm, which has likely formed fresh wind slabs and created new cornice growth. The storm snow has buried a widespread melt-freeze crust which was thought to exist almost everywhere, the exception may be high elevation north facing terrain. A widespread crust/facet layer from early February and depth hoar at the bottom of the snowpack (primarily in northern & inland areas) has gone dormant for the time being. These layers have the potential to wake up during periods of prolonged warming.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.