Avalanche Forecast

Issued: Mar 21st, 2018 4:00PM

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

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

Not quite spring "Low", main concerns are deeper facets in thin areas, buried sun crust on solar aspects, and wind slab in lees. Generally great skiing can be found on North aspects.

Summary

Weather Forecast

The unsettled weather continues again on Thursday generally cloudy with flurries moving into the region Thursday night. Flurries will continue through to Saturday with accumulations ranging from 10-15 cm.. Friday might be the snowiest day this week and temperatures are forecast to fall below -15 for the start of the weekend.

Snowpack Summary

Convective flurries have deposited new snow in some areas of the park and not so much in others, so the surface conditions are quite variable. Localized windslabs were created earlier in the week and have been reactive. On south and west aspects these slabs may bond poorly to a suncrust down approximately 30-50 cm.

Avalanche Summary

A size 1 windslab was triggered by skiers on a classic leeward slope under a cornice Tuesday - 25 cm deep by 50 m wide. Several large avalanches were triggered earlier in the week. The common theme has been West aspect on suncrust (Amiskwi area - W. of Yoho). In thin areas, the Observation Peak avalanche, released on a deeper layers.

Confidence

Problems

Wind Slabs

Localized winds have created slabs up to 30 cm thick in some drainages, in other areas they are much thinner and restricted to the immediate lees. They are unlikely to release naturally but can be triggered by skiers and climbers.

Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

On steep solar terrain the recent storm snow (10-30cm) is sitting on a suncrust. In thinner areas the have been 2 avalanches on deeper facet layers. These problems tricky due to their isolated nature - caution on solar aspects and in thin areas.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Mar 22nd, 2018 4:00PM