Avalanche Forecast

Issued: Jan 10th, 2019 8:16AM

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

danyelle magnan, Parks Canada

Glacier.

The warming trend is promoting slab development which may be reactive to skiers. Over the weekend, above freezing temperatures and sunshine are expected to trigger avalanches.

Summary

Weather Forecast

The warming trend that started yesterday will continue over the weekend, when a strong ridge is expected to develop. Flurries will taper off today and we may see some sunny breaks. Alpine temps of -3'C and light but gusty SW winds are expected. Fri will be similar. On Sat things heat up with alpine temps to +3'C and freezing levels rise to 2800m.

Snowpack Summary

Nearly 50cm of snow has fallen in the past 4 days. On southerly aspects, NE winds yesterday will have reverse loaded lees creating deeper pockets of soft slab. In exposed alpine areas and a ridge crest it will have buried old windslabs. The Jan 2 freezing rain crust is down ~90cm. The Nov 21st interface is now 1-2m in deep.

Avalanche Summary

Yesterday, 4 size 2.5 and one size 3 natural avalanches were observed from steep slopes. In the region, skiers reported triggering storm slabs. On Wed, skiers accidentally triggered a size 3.5 as they approached Camp West. The crown was 40cm deep where triggered and up to 1.5m deep. Width of the crown was well over 100m and ran over a kilometer!

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Storm Slabs

Continued snowfall, combined with mild temps, will have created soft storm slabs in many areas. In the region, storm slabs have been reactive and easily triggered by skiers. Be especially cautious in alpine areas, where it has buried windslabs.

Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.Ski short pitches and regroup in safe spots.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

The recent size 3.5 skier triggered avalanche highlights that in some areas persistent slabs may be reactive. The problem likely woke up with rapid wind loading and significant new snow in January, and was triggerable where the snowpack was shallow.

Caution on steep solar aspects where the snowpack is thin and or cross loaded.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2.5 - 3.5

Valid until: Jan 11th, 2019 8:00AM