Avalanche Forecast
Issued: Jan 12th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Loose Dry and Persistent Slabs.
Jeff Andrews,
Hwy 93 will be closed 1700hrs January 12 Atha Falls to Sask Crossing with tentative opening January 14 late morning.
Be mindful of overhead exposure and terrain choice as we are expecting a descent avalanche cycle in the next couple days.
Summary
Weather Forecast
A strong warm frontal system will bring moderate to heavy precipitation overnight Tuesday into early Wednesday (up to 40cm). Southerly winds will increase to moderate and strong values. The freezing level will rise up to 1600m overnight Tuesday falling to valley bottom mid day Wednesday. A clearing trend will follow.
Snowpack Summary
Up to 40cm of snow is forecast overnight Tuesday into Wednesday accompanied by moderate to strong southerly winds. The freezing level may reach 1600m; rain is likely at lower elevations. The new snow will fall upon a supportive mid pack except regions with a shallow snowpack like the Maligne range. Basal snowpack is weak facets and depth hoar.
Avalanche Summary
No new avalanche activity observed or reported; no patrol today.
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Confidence
Forecast snowfall amounts are uncertain
Problems
Storm Slabs
Wind slab developing on lee aspects in the alpine and open tree line; storm slab building all aspects tree line and below. January 12 interface includes previous hard slab in the alpine and patchy surface hoar sheltered tree line and below tree line.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
- Use caution in lee areas. Recent wind loading has created reactive slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Dry
Ice climbers be wary of this problem as even small avalanches can have serious consequences. Wet loose in steep terrain below treeline may also become a problem depending on the freezing level and potential rainfall.
- Minimize overhead exposure during periods of heavy loading from new snow, wind.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Use caution around thin to thick areas where buried deeper weak layers could be triggered. The surface hoar layer down 40-70cm seems unreactive and spotty distribution but keep it on your radar especially with the new snow load.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 13th, 2021 4:00PM
