Avalanche Forecast

Issued: Feb 12th, 2014 4:18PM

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

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

Small natural cycle occurring in the alpine. Very touchy wind and storm slab condition exists. It's definitely time to pick more conservative lines or routes.

Summary

Weather Forecast

Another 5 cm forecasted for Thursday and 5 for Friday with moderate to strong SW winds is forecasted for the next few days.

Snowpack Summary

A touchy 15-30 cm soft wind/storm slab is not bonding well to underlying surfaces (surface hoar, facets, and suncrust) formed from the past three weeks of cold, dry weather. With additional snow forecast over the next few days, expect the soft slabs to increase in depth and size.

Avalanche Summary

A natural cycle was occurring in the alpine, but visibility was poor. Across the region, several soft touchy windslabs 15-30 cm deep (size 1.5) have been ski cut on all aspects above treeline. Propagations were generally 10-40 m. A general observation was small avalanches were running far an fast, up to 700 m in one case in KNP.

Confidence

Due to the quality of field observations

Problems

Wind Slabs

The 10-20 cm of new snow has created touchy windslabs up to 30 cm thick with impressive propagations for their small size.

Avoid freshly wind loaded features.Avoid areas with overhead hazard.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely - Certain

Expected Size

1 - 2

Storm Slabs

The new snow now has enough cohesion in some locations to act as a soft slab on steeper features not affected by the wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

This dormant layer may start to wake up over the next few days with continued snow and wind loading, we are monitoring it closely. It is a weak basal facet layer that is a problem on the East side of the Divide (Lake Louise area).

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Feb 13th, 2014 4:00PM