New snow and strong winds are building reactive storm slabs.
Freezing levels are uncertain: Snow may fall as rain at lower elevations.
Up to 25 cm of new snow combined with strong west to southwesterly winds will build reactive new storm slabs. These slabs will be thickest and most reactive on lee slopes near ridgetops.
Wet loose avalanches may be possible if the sun comes out with enough force on Sunday. Back off of sunny slopes if you notice the snow surface getting moist.
On Thursday, several warming-induced wet loose and glide slab avalanches were reported in the McGregors up to size 3 on all aspects and elevations.
On Wednesday, several natural slab avalanches up to size 2.5 were reported.
Looking forward, with the forecast snow and wind building fresh storm slabs, we expect natural avalanches to be possible, and human-triggered avalanches to be likely on Sunday.
Around 15 to 25 cm of new snow is covering a thick melt-freeze crust that exists up to around 2000 m and on all solar aspects. Some of the new snow may have fallen as rain at lower elevations. Forecast strong west and southwesterly winds will be building thicker and more reactive storm slabs on lee north and easterly slopes.
The late January persistent weak layer, consisting of surface hoar/facets/crust, is buried 40 to 70 cm. This layer is now expected to be generally dormant due to the thick crust bridging overtop. Lingering concern for triggering this layer remains on steep, high alpine northerly slopes above 2000 m.
Saturday Night
Mostly cloudy. 5 to 20 cm of snow. 50 km/h west ridgetop wind. Treeline temperature -2 °C. Freezing level 1700 m dropping to valley bottom.
Sunday
Mix of sun and clouds. 40 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level rising to 1300 m.
Monday
Mix of sun and clouds. 0 to 5 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level rising to 1200 m.
Tuesday
Mostly cloudy. 5 to 10 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level rising to 1300 m.
More details can be found in the Mountain Weather Forecast.
