Our persistent weak layer is getting more sensitive.
Dangerous avalanche conditions exist and several evidences are observed.
Adopt a conservative mindset when in avalanche terrain.
Flurries and elevated winds should create new reactive wind slabs. Small wind slab releases may step down to weak layers in the upper snowpack to produce larger, more destructive avalanches.
Recent snow and wind have been working to consolidate reactive slabs over the mid-February weak layer and the late January crust below it. Shaded, wind-loaded areas at higher elevations are the most likely places to trigger this problem.
A large-scale natural avalanche cycle (size 3) was observed after Sunday's storm from steep northerly slopes at treeline and above. Several skiers-remote persistent slabs were also reported on the persistent layers down 40 to 50 cm deep in the snowpack in the region. See this MIN near Rohr Summit. There are reports of wind contributing to slab development over this layer.
10 to 20 cm of new snow accumulated overnight Sunday, bringing the total of storm snow to 50 to 60 cm and overlying various problematic surfaces formed during recent cold, dry conditions. These include weak surface hoar or faceted grains in sheltered, shaded terrain, and sun crusts on sun-affected slopes. This layer was responsible for numerous remote triggered observed Sunday and Monday in the region.
A layer of hard crust buried in late January, currently sitting beneath weak facets and less widespread surface hoar is now 40 to 80 cm deep. Some recent avalanches have failed on it. It's particularly active closer to Whistler.
The snowpack below is strong.
Monday Night
Cloudy with 5 to 10 cm of new snow. 30 to 50 km/h south ridgetop wind. Treeline temperature stable around -4°C. Freezing level around 1400 m.
Tuesday
Mostly cloudy with isolated flurries. 15 to 25 km/h southwest ridgetop wind. Treeline temperature stable around 0°C. Freezing level reaching 1700 m.
Wednesday
Partly cloudy. 20 to 30 km/h south ridgetop wind. Treeline temperature stable around +2°C. Freezing level reaching 2200 m.
Thursday
Cloudy with up to 5 cm of new snow. 40 to 60 km/h southwest ridgetop wind. Treeline temperature +2°C. Freezing level lowering to 1800 m.
More details can be found in the Mountain Weather Forecast.
