The persistent slab is alive and well producing very large avalanches over the past few days.
Natural avalanches may taper but human triggering is likely.
The persistent slab avalanche problem has resulted in large to very large avalanches (up to 3.5). Natural avalanche activity will start to taper but human triggered avalanches remain likely.
Watch for newly formed and reactive storm slabs. Northeast slopes likely hold deeper slabs due to wind loading.
Potential remains for slabs to step down to deeper persistent weak layers.
On Thursday, natural avalanche activity continued up to size 2 with a persistent slab size 3.5 reported.
Natural avalanche activity will likely taper over the weekend but the snowpack may be primed for human triggering.
40 to 80 cm of storm snow fell across the region earlier in the week. Strong to extreme west through southwest wind created widespread wind-loading, with deeper deposits of snow found on leeward slopes. The winds are forecast to change directions which may start to wind- load southerly aspects throughout the weekend.
At upper elevations down 30 to 60 cm a layer of surface hoar, facets, or a thin crust exists.
A persistent weak layer of surface hoar and facets overlying a crust is buried 100 to 200 cm deep. This layer was reactive during the storm, producing large and dangerous avalanches.
Friday Night
Partly cloudy. 10 to 20 km/h north ridgetop wind. Treeline temperature -8 °C.
Saturday
Mix of sun and cloud. 10 to 25 km/h northwest ridgetop wind. Treeline temperature -10 °C.
Sunday
Cloudy with sunny periods. 10 to 20 km/h northeast ridgetop wind. Treeline temperature -8 °C. Freezing level valley bottom. Strong alpine above freezing layer.
Monday
Cloudy with some sunny periods and isolated flurries. 20 gusting to 45 km/h southwest ridgetop wind. Treeline temperature -5. Freezing level valley bottom.
More details can be found in the Mountain Weather Forecast.
