Avalanche Forecast

Issued: Feb 10th, 2017 5:18PM

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

Avalanche Canada mgrist, Avalanche Canada

Human triggered avalanches remain likely on Saturday at treeline and above. Use small slopes with low consequence to test the bond of the storm snow.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Seasonal temperatures and isolated flurries through the weekend. Significant warming Monday onwards. SATURDAY: 15-20cm possible for the Coquihalla and Duffey zones by Saturday morning. Mostly cloudy with isolated flurries. / Light to moderate southwesterly winds/ Freezing level around 900 m / Alpine highs to -7 Celsius SUNDAY: Cloudy with sunny breaks / Light, southwesterly winds / Freezing level rising to 1400 m in the afternoon. MONDAY: Sunny with cloudy periods, warming significantly with highs to +1 Celsius / Moderate southwesterly winds / Freezing level around 2000 m.

Avalanche Summary

A widespread natural avalanche cycle (to Size 2.5) occurred on all aspects and elevations at treeline and above from Thursday into Friday. 

Snowpack Summary

An additional 40+ cm of snow on Thursday added to the 35-50 cm (lower amounts in the north) of recent storm snow. Temperatures rose on Thursday afternoon, increasing the likelihood slab avalanches with the heavier snow on top of lighter, drier snow. All this storm snow is sitting on a wide variety of old snow surfaces including stiff wind slab or wind effected snow at upper elevations, sun crust on steep southerly slopes, surface hoar and surface facets in sheltered locations. The mid-January surface hoar and facet interface is now buried 90-120 cm and the mid-December facets down 130-160 cm still remain a concern especially in shallower snowpack areas in the Duffey, Hurley and/ or South Chilcotins. These deeper weaknesses warrant monitoring, especially through periods of rapid loading. In southern areas (Coquihalla), the lower snowpack is reportedly well settled (stronger), than it is to the north.

Problems

Storm Slabs

An icon showing Storm Slabs
Continued snow and wind are making the existing storm slabs increasingly dangerous.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Use caution in lee areas in the alpine and treeline. Storm snow is forming touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
This problem is more prevalent in the far north areas of the region and is a low likelihood, high consequence scenario that will need to be monitored as snow loads increase.
Be cautious in shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Feb 11th, 2017 2:00PM

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