Avalanche Forecast
Regions: Banff Yoho Kootenay.
Lots of uncertainty with incoming weather systems, more snow expected west of Divide and Northern part of the region.
If we receive less snow than forecasted the hazard will remain in the Considerable range.
Weather Forecast
5-15 cm forecasted for tonight and tomorrow, coupled with westerly winds and temperatures increasing through the day will correspondingly elevate the avalanche hazard. Another storm is expected Saturday bringing even more snow, wind, and temperatures will start to cool.
Snowpack Summary
10-15 cm over the past 2 days. The alpine has been hammered by W wind creating wind slabs in the alpine to treeline. Generally, the upper snowpack of denser snow sits over a weak lower snowpack consisting of facets, depth hoar and crusts. At treeline, new snow sits on pockets of surface hoar in sheltered areas and sun crust on steep solar aspects.
Avalanche Summary
Natural and explosive triggered size 1 wind slabs today in lee alpine terrain, 20-50 cm thick and propagating 15-30 cm. One natural size 2.5 off Mt. Bourgeau in an alpine feature that had slid in the last storm but has since reloaded.
Confidence
Intensity of incoming weather systems is uncertain
Avalanche Problems
Wind Slabs
20-50 deep reactive wind slabs propagating 15-30 m wide. Heightened caution at treeline where new snow will load buried surface hoar in sheltered locations or sun crust on steep solar.
- Use caution in lee areas. Recent wind loading has created wind slabs.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Deep Persistent Slabs
Continued reports of whumphing on the weak, faceted lower snowpack indicate the potential for human triggering. This likelihood will rise with new snow and wind over the next few days. Triggering the deep facets could result in a large avalanche.
- Be aware of the potential for wide propagations which could result in large avalanches.
- Avoid shallow snowpack areas where triggering is more likely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3
Loose Dry
A problem primarily in steep gully features due to the ongoing wind and new snow forecasted. Ice climbers consider the overhead hazard and the possibility of windslabs being triggered by loose dry.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1.5