Avalanche Forecast
Regions: Boundary, East Stikine, Kispiox, Ningunsaw, Northwest Coastal, Northwest Inland, Stewart, West Stikine.
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.
Confidence
Moderate
Avalanche Summary
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.
Snowpack Summary
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.
Weather Summary
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.
Terrain and Travel Advice
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Avoid freshly wind-loaded terrain features.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Keep in mind that human triggering may persist as natural avalanches taper off.
Avalanche Problems
Persistent Slabs
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.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3.5
Storm Slabs
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.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2