Avalanche Forecast

Issued: Feb 5th, 2015 8:16AM

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

Avalanche Canada triley, Avalanche Canada

Strong winds, heavy snowfall, and rising temperatures have resulted in HIGH avalanche danger.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Heavy snow and strong Southerly winds overnight and Friday morning. Freezing levels climbing up to about 1500 metres in the North and east of the region, and closer to 1800 metres in the Southwest of the region. Strong Southerly winds continuing on Friday and Saturday morning. Freezing levels dropping to 1400 metres on Saturday afternoon as the winds slow to moderate Southwest. Light Southerly winds combined with light precipitation and cooler temperatures on Sunday.

Avalanche Summary

There were a couple of size 1.0 storm slab avalanches on Wednesday that were triggered by skiers. The storm slab was reported to have settled into a more cohesive slab with the warming temperatures. Expect natural avalanche activity and avalanche size to increase with storm loading.

Snowpack Summary

The storm slab continues to develop and is 40-60 cm thick and sits on a variety of old surfaces including crusts, surface hoar, and old wind slabs. Ski penetration has been reported to be about 50 cm in the North of the region. A crust can be found below about 1900m in the north of the region and below 2200m in the south of the region. At higher elevations the new snow covers old wind slabs formed by moderate southwest winds. Several persistent week layers can be found deeper in the snowpack that may be capped by the overlying crust at lower elevations. The mid-January surface hoar is buried between 40 and 80cm down and remains a concern at treeline and above. The mid-December surface hoar layer is now 80 to 140cm below the surface and appears to be slowly gaining strength.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow and strong winds are expected to continue to develop storm slabs on all aspects and at all elevations. Expect widespread natural avalanche activity and easy triggering from human activity.
The new snow will requires several days to settle and stabilize.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

2 - 5

Persistent Slabs

An icon showing Persistent Slabs
Buried persistent weak layers may be over-loaded by the forecast new storm snow resulting in human triggering, or storm slab avalanches in motion stepping down to the deeply buried weak layers.
Pay attention to overhead hazards like cornices.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Feb 6th, 2015 2:00PM