Avalanche Forecast
Regions: South Coast Inland.
Assess for instability before committing to consequential terrain.
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
THURSDAY NIGHT: Increasing clouds with no precipitation, 20 to 30 km/h southwest wind, alpine temperature -8 C.
FRIDAY: Cloudy with snowfall, accumulation 1 to 3 cm, 30 to 50 km/h southwest wind, alpine temperature -6 C.
SATURDAY: Cloudy with snowfall, accumulation 2 to 5 cm, 30 km/h south wind, alpine temperature -5 C.
SUNDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 30 km/h southwest wind, alpine temperature -5 C.
Avalanche Summary
A rider triggered a persistent slab avalanche along the Duffey on Wednesday, occurring at 2000 m on a northeast aspect. Another suspected persistent slab avalanche was triggered by a rider on Tuesday in the north of the region. Both slabs were around 30 to 40 cm thick, resulting in small avalanches (size 1 to 1.5). It remains possible that humans could trigger this layer, where it exists.
Looking forward, wind slabs may begin to form on Friday and into the weekend, which may not bond well to underlying layers.
Snowpack Summary
New snow will fall with strong wind, potentially forming small wind slabs in lee terrain features. The snow will accumulate onto variable surfaces. On sun-exposed slopes and on all aspects at low elevations, the snow will build on a hard melt-freeze crust. Elsewhere, it will fall onto previously wind-affected snow at higher elevations and perhaps a thin layer of surface hoar or faceted snow in sheltered areas.
Around 30 to 60 cm deep, sugary faceted grains may be found around a melt-freeze crust that formed February in the north of the region (e.g., Duffey, Hurley). To date, the layer has been most prevalent on north to northeast aspects around 1900 to 2100 m. This layer should be treated as suspect anywhere it exists. Check out this forecaster blog for more info. Various crusts may be found in the south of the region (e.g., Coquihalla, Manning) but reports suggest they are bonding to the snowpack and are not an avalanche concern.
There are no deeper concerns at this time.
Terrain and Travel
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Avalanche Problems
Persistent Slabs
Portions of the north of the region (e.g. Duffey, Hurley) have a a weak layer of faceted grains above a hard melt-freeze crust that is found 30 to 60 cm below the snow surface. A few avalanches over the past week have released on it, with more activity observed in the neighbouring Sea to Sky region. It has been most problematic in the region on north to northeast aspects around 1900 m to 2100 m.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2.5
Wind Slabs
New wind slabs may start to form as new snow accumulates with southwest wind. Resulting slabs are expected to be quite small but they may not bond well to the snowpack.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 1.5