Avalanche Forecast
Regions: Northwest Inland.
Current snowpack and weather conditions are highly variable throughout the region. Dangerous avalanche conditions exist where new snow accumulations or wind loading exceeds depths of 25 cm.
Confidence
Low - Uncertainties in both the snowpack structure and the weather forecast limit our confidence.
Weather Forecast
Tuesday night: Scattered flurries accumulating to 5 cm overnight, moderate wind from the southwest, alpine temperatures around -3 C freezing level around 1000 m.
Wednesday: Snow with accumulations of 5-15 cm, strong wind from the west, alpine temperatures drop from -2 to -12 C through the day, freezing level drop to valley bottom.
Thursday: Mix of sun and cloud with isolated flurries, moderate wind, alpine high temperatures around -10 C.
Friday: 5-10 cm of snow, moderate wind, alpine high temperatures around -8 C.
Avalanche Summary
Stormy weather is likely forming unstable storm slabs and wind slabs, as well as adding stress to buried surface hoar layers. There are reports of recent large natural avalanches in the Telkwa Range (size 2-3), mostly on northeast aspects. Some were likely triggered by cornices, while many appear to have run on the buried surface hoar layers. A size 1.5 skier-triggered avalanche was reported in the Ashman area on Friday. The avalanche occurred on a convex north-facing slope at treeline and also failed on a surface hoar layer 50 cm below the surface (see full report and photos in this MIN post).
Snowpack Summary
Recent snowfall amounts as well as forecast snowfall amounts vary widely for Wednesday, but there are likely storm slabs developing in parts of the region. Reports suggest there are two layers of surface hoar buried 25-50 cm below the surface. A skier triggered avalanche at Ashman and snowpack test results near Smithers suggest these layers have now become reactive. There is uncertainty about the distribution of this layer, but the sheltered slopes around treeline elevations are the most suspect for having preserved surface hoar.
Terrain and Travel
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Dial back your terrain choices if you are seeing more than 25cm of new snow.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
Avalanche Problems
Wind Slabs
New snow coupled with increasing wind are expected to form unstable slabs especially in alpine lees.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2
Persistent Slabs
Recent reports of avalanches on buried surface hoar layers (including this MIN report) suggest that a persistent slab problem has developed. Persistent slabs will become more reactive with the additional load of new snow. While there is uncertainty about the distribution of this problem, sheltered slopes around treeline elevations are most the suspect. Large, deep avalanches have the potential to run below treeline, elevating hazard there.
Aspects: North, North East, East, North West.
Elevations: Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 3