Avalanche Forecast
Regions: Boundary, Howson, Kitimat, Microwave-Sinclair, Nass, Northwest Coastal, Rupert, Seven Sisters, Shames, Stewart.
Reactive wind slab conditions were reported from the Shames area, a good starting point for your analysis. Start small and check for signs of instability before committing to your line.
Confidence
Moderate
Avalanche Summary
A MIN report from the Shames area on Wednesday describes wind slab formation and reactivity to skier traffic that has helped confirm active conditions in the south of the region.
Steadier reports of wind slab avalanches have been coming from the north, where recent snowfall has been greater and avalanches up to size 3 have been focused around north aspects in the alpine. A natural size 2.5 persistent slab that failed on the early-December crust was seen overnight Wednesday.
Snowpack Summary
Up to 60 cm of recent snow overlies previously wind affected surfaces in the alpine and at treeline. Roughly half this amount accumulated on Wednesday through Thursday and has fed into new wind slab development. You'll likely find moist surface snow or thin accumulations on crust below 900 m.
Below these surface layers, two distinct weak layers exist in the top meter of the snowpack. A layer of facets and/or surface hoar down 30 to 50 cm and the early December crust down 50 to 90 cm. Recent observations of these layers in the south of the region are limited.
Treeline snow depth range from 200-280 cm. The lower snowpack has no layers of concern.
Weather Summary
Thursday night
Cloudy with continuing scattered flurries and less than 5 cm of new snow. 30 to 40 km/h southwest ridgetop wind. Freezing level 800 m.
Friday
Cloudy with increasing flurries bringing a trace to 10 cm of new snow, continuing overnight. 20 to 40 km/h south ridgetop wind. Freezing level 700 m with treeline high temperatures around -2 °C.
Saturday
A mix of sun and cloud. 10 to 15 km/h northeast ridgetop wind. Freezing level returning to surface and treeline temperatures dropping to -6 °C.
Sunday
Partly cloudy with easing isolated furries. 5 to 10 km/h variable ridgetop wind. Treeline high temperature around -4 °C
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- Start with conservative terrain and watch for signs of instability.
- Be aware of the potential for large avalanches due to buried weak layers.
Avalanche Problems
Wind Slabs
Recent steady snowfall and elevated winds have been forming fresh wind slabs. Friday's forecast promises more of the same scenario.
Surface avalanches may have potential to step down to weak layers in the top metre of the snowpack.
Aspects: North, North East, East, West, North West.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2