Regions
Northwest Coastal.
New storm slabs may take a couple of days to settle and bond depending on the old surface beneath.
Confidence
Fair - Due to the number and quality of field observations
Weather Forecast
Light snowfall is forecast overnight as an upper level LOW pressure system moves onshore between Prince Rupert and Stewart. Moderate winds at ridgetops should be out of the east-southeast in front of the LOW and switch to the west-southwest after the quick passage of the system. Freezing levels should drop down to about 500 metres and remain there during the day on Friday. Expect 5-10 cm of snow above 500 metres elevation by Friday morning and another 3-7 cm during the day. The next system is steaming towards the south coast on Saturday, however an Arctic front that is descending from the north may not allow much moisture to get north of the central BC coast.
Avalanche Summary
No new avalanches reported. New storm slabs should settle over night and forecast cooler temperatures may help improve stability.
Snowpack Summary
A report from Shames on Wednesday states that the freezing level was about 850 metres elevation with 10-15 cm of new snow at treeline and 15-20 cm at the ridge. Providing good quality skiing in well consolidated snow above a non breakable crust. The regional snowpack is highly variable across different aspects and elevations. So far, we only have limited information from the field. Initial reports suggest that there is around 150 cm at 2000 m. Recent winds have scoured exposed slopes, and left variable wind slabs and crusts. In some places, a crust/facet interface or surface hoar can be found in the upper snowpack. At high elevations, a crust which formed early season may exist near the base of the snowpack. The new storm snow may not bond well to the mix of old surfaces left behind after the recent high pressure. Buried surface hoar may be found below the new storm snow at lower elevations, or in areas where the recent temperature inversion was not strong enough to melt it.
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.