Avalanche Forecast

Issued: Feb 23rd, 2019 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 Loose Dry.

Tim Haggarty, Parks Canada

Banff Yoho Kootenay.

Travellers should watch for windslabs as they reach treeline and become selective with the terrain they consider. Ice climbers and skiers alike should be wary of loose snow sluffs in steep terrain at all elevations.

Summary

Weather Forecast

Arctic air is taking over yet again. Alpine winds will be from the N and diminishing from moderate Saturday to light Sunday and almost calm Monday before picking back up again through the day. While skies will trend towards clear on Monday Tuesday , temperatures willÂ creep a few degrees colder reaching -25C in the alpine.

Snowpack Summary

20 to 40 cm has accumulated since Feb 1 along with isolated crusts on steep solar slopes and wind effect treeline and above. In isolated areas at treeline and below the Jan 17 surface hoar can be found down 30-60 cm, and is producing hard but sudden test results. Weak basal facets can be found in thinner snow pack areas.

Avalanche Summary

Small thin natural wind slabs and loose dry avalanches up to size 2 have been observed out of very steep alpine terrain over the past couple days with loose dry avalanches running down into treeline. Skier triggered loose dry sluffing of the surface facets has also been observed in steep terrain at all elevations up to size 1.

Confidence

Problems

Wind Slabs

A mix of new wind slabs and old buried slabs have been found on various aspects that continue to be worth watching for in steep terrain. While these are more isolated and of smaller size at treeline they still warrant careful terrain selection.

Variable winds may create pockets of wind slab in some unexpected locations.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

A sustained period of cold weather has created weak, dry, faceted surface snow. In steep terrain, these facets are sensitive to small natural and human triggers and can quickly gain enough mass to affect skiers and climbers, especially in gullies.

Good group management is essential to manage current conditions safely.Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Feb 24th, 2019 4:00PM