Avalanche Forecast

Issued: Feb 20th, 2019 4:00PM

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

stephen holeczi, Parks Canada

Little Yoho.

Its a mixed bag of wind effect and powder at treeline and above. Thursday looks like a nice day but watch for pockets of wind slab or heavy sluffing in very steep terrain.

Summary

Weather Forecast

A cold morning (-20C) for Thursday in Little Yoho rising to around -10C in the afternoon. It looks to be a clear day with light winds throughout the region. Friday is calling for a small system (only a couple cm of snow) but alpine winds are forecast to be in the strong range from the West before settling down on Saturday.

Snowpack Summary

30 to 50 cm of snow has fallen since Feb 2. Recent new snow has been affected by light to moderate westerly winds. Cold conditions continue promoting faceting of the snowpack. Down 30 to 75cm, Jan 17 surface hoar produces sudden planar shears in isolated locations treeline and below. A weak basal snowpack exists in shallow areas.

Avalanche Summary

A size 2.5 was reported by Sunshine ski hill today. It was a wind slab in the alpine that was 1m deep likely caused by winds from yesterday. Some other loose dry avalanches were noted in the backcountry and numerous wind slabs have been triggered (size 1-2) over the past week. No activity was noted on Mt. Field today but plenty of wind effect .

Confidence

Problems

Wind Slabs

A mix of old and new wind slabs have been found on various aspects that in the short term will be something to watch for in the terrain.

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 driven the faceting process in the upper snowpack creating weak, dry surface snow. In steep terrain, these are sensitive to small natural and human triggers and can quickly gain enough mass to affect travelers.

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: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Feb 21st, 2019 4:00PM