Avalanche Forecast
Regions: Banff Yoho Kootenay.
Lots of weather inputs which should prompt people to be very conservative with both the terrain they are traveling in and exposure to overhead terrain. The Considerable rating below treeline is for runout zones of large avalanche paths only.
Weather Forecast
Cooling temperatures to -15C in the alpine for Sunday. Winds will be in the moderate range with the odd strong gust at treeline and above, and around 5cm is in the forecast. The cooling trend continues Monday and another pulse of snow is expected on Tuesday.
Snowpack Summary
20-40 cm of storm snow, strong Westerly winds and mild temperatures is promoting storm slab formation. Generally, the upper snowpack of denser snow sits over a weaker lower snowpack consisting of facets, depth hoar and crusts. At tree line, new snow sits on pockets of surface hoar in sheltered areas and sun crust on steep solar aspects.
Avalanche Summary
Some increasing natural activity today with the strong winds. A size 3 on Mt. Field, a size 2.5 on Vermillion Peak, and another size 2.5 slide in the Sunshine area were directly observed today. We suspect there is a natural cycle occurring currently which will continue as long as the wind keeps up.
Confidence
Wind effect is extremely variable
Avalanche Problems
Storm Slabs
The 20-40cm of storm snow has been accompanied by strong Westerly winds. Thick slabs in the lees of alpine and treeline features are likely forming due to the winds, and lower down the snow is settling into a slab.
- Use caution in lee areas. Recent wind loading have created storm slabs.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2.5
Deep Persistent Slabs
Lots of uncertainty surrounding this layer and what will trigger it with all of the new inputs of snow, wind and warm temperatures. 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 - 3.5
Loose Dry
While the wind stays elevated loose dry avalanches will be a problem in gully features.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1.5