Avalanche Forecast

Issued: Feb 4th, 2017 5:14PM

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

Avalanche Canada jsmith, Avalanche Canada

Touchy storm slabs reactive to human triggers. Conservative decision making will be CRITICAL to playing safe in the mountains this weekend.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Saturday night: 20-25 cm new snow / Moderate to strong, southwest winds / Freezing level sea level.Sunday: 0-5 cm new snow / Moderate, southwest winds/ Freezing level sea level.Monday: Mostly cloudy with flurries / Light to moderate, southwest winds / Freezing level sea level.Tuesday: Mix of sun and cloud / Light, southwest winds/ Freezing level sea level.

Avalanche Summary

New storm slabs will likely have a poor bond to the old snow surfaces and be reactive to human triggers, especially on leeward slopes that are more wind loaded. In thin areas to the north, storm slabs could potentially step-down to deeper weak layers.

Snowpack Summary

15-25 cm of new snow has buried 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. An additional 20-25 cm of new snow is expected by Sunday morning, bringing storm totals up to 35-50 cm(lower amounts in the north). The mid-January surface hoar and facet interface is now buried 50-80 cm and the mid-December facets down 90-120 cm remain a concern especially in shallower snowpack areas like the Duffey, Hurley and/ or South Chilcotins. These deeper weaknesses warrant monitoring especially through periods of more load. 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
Touchy storm slabs reactive to human triggers. Smaller storm slabs may step-down to deeper weak layers, resulting in large, destructive avalanches.
The new snow will require several days to settle and stabilize.Use conservative route selection, choose moderate angled and supported terrain with low consequence.Watch for signs of instability such as whumpfing, shotting cracks, or recent natural avalanching.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very 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.
Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Feb 5th, 2017 2:00PM

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