Avalanche Forecast

Issued: Feb 6th, 2018 4:20PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Persistent Slabs and Wind Slabs.

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Touchy conditions persist. If avalanches are triggered, expect deep fractures and wide propagations. The better choice is to avoid avalanche terrain.

Summary

Weather Forecast

The next storm should arrive early Wednesday. By Thursday we could see accumulations of up to 35cm. Moderate wind from the SW and temps near zero will accompany the storm cycle.

Snowpack Summary

Storms from the last 9 days have deposited up 100cm of storm snow. The main concern in the snowpack lurks below and continues to be the 3 persistent weak layers of surface hoar and/or facets that are found between 50 and 100cm down. We continue to observe sudden test results, whumphing and large propagations on these layers.

Avalanche Summary

Lake Louise ski area reported triggering a large size 3 avalanche with explosives today. At the very end of the day Visitor Safety responded to a potential involvement on Quartz Ridge. It ended up be a remote triggered size 3 from a recreational party with no involvement.

Confidence

Intensity of incoming weather systems is uncertain on Thursday

Problems

Persistent Slabs

Three weak layers exist in the upper snowpack: Jan 16, Jan 6, and Dec 15. All are a mix of sun crust, surface hoar and facets depending on the aspect and elevation. 50-100 cm of snow over the last week has overloaded these layers.

Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 3.5

Wind Slabs

Increased wind at high elevations has created wind slabs in lee areas. The slabs are up to 100cm thick.

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Feb 7th, 2018 4:00PM