Avalanche Forecast
Issued: Jan 3rd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Deep Persistent Slabs and Loose Dry.
mark herbison,
Parks Canada
Continued snow, strong winds and mild temps will keep the avalanche hazard elevated. Choose low consequence terrain and minimize exposure to overhead avalanche hazard.
Summary
Weather Forecast
5-20cm of snow forecasted for tonight and into Saturday, accompanied by strong Westerly winds. Temperatures are forecasted to drop gradually with an Alpine high of -10. Another 5-10cm on Sunday as the winds drop slightly.
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 weak 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
Natural avalanche activity up to sz 2 within the storm slab. Reports of skier triggered and skier remote avalanches up to sz 2 in the Yoho region, no involvements. Local ski areas were getting explosive results up to sz 2 within the storm slab from steep alpine features, crown depths 20-40cm deep.
Confidence
Problems
Storm Slabs
The 20-40cm of storm snow is being redistributed by the strong Westerly winds and settling into a storm slab. Heightened caution at tree line where new snow has buried surface hoar in sheltered locations or sun crust on steep solar.
- 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: Alpine, Treeline.
Likelihood
Expected Size
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
Expected Size
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 storm slabs being triggered by loose dry.
- If triggered dry loose point releases can form deeper deposits in terrain traps.
- Be careful of loose dry power sluffing in steep terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 4th, 2020 4:00PM
