Avalanche Forecast

Issued: Jan 9th, 2018 4:19PM

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 pgoddard, Avalanche Canada

New snow is adding stress to touchy weak layers in the snowpack.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

WEDNESDAY: Moderate westerly winds. 5-15 cm snow. Alpine temperature near -12.THURSDAY: Moderate to strong westerly winds. Light snow. Alpine temperature near -15.FRIDAY: Strong westerly winds. Light snow. Alpine temperature near -15.

Avalanche Summary

Recent observations include naturally-occurring slab avalanches at around 1900 m and ongoing reports of touchy conditions, with whumpfing and cracking observed. As snow continues to fall, avalanche activity is expected to increase.A timber sledder triggered and was caught in a small avalanche on a road cut on Sunday. It occurred a little below treeline, south of the Crowsnest. Avalanche conditions seem especially touchy in this type of terrain right now.

Snowpack Summary

A volatile weak layer from mid-December (predominantly feathery surface hoar crystals and/or a sun crust) is found at treeline and below. Slabs can fail very easily on this layer, either naturally or with the weight of a person or machine. Every extra snowflake adds stress to this layer.The snowpack is variable across the region, but persistent slabs are a generally widespread problem. Wind slab and storm slab distribution will be more variable. Hard wind slabs can be found in parts of the region due to recent extreme south-west winds. Windward alpine slopes may be scoured; and variable wind slabs are found at treeline and alpine elevations. New snow is likely to fail as storm slabs and/or loose avalanches. Deeper in the snowpack, an early season rain crust and sugary facets make up the picture. An avalanche in motion could step down to these deeper layers, creating a surprisingly large avalanche. Overall snowpack depths are variable across the region. It's generally shallower in the east.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow is likely to fail as loose snow or slab avalanches, especially in steep alpine or treeline terrain.
Use ridges or ribs to avoid areas of wind loaded snow.Back off if you encounter whumpfing, hollow sounds or shooting cracks.Use conservative route selection. Choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
New snow may overload an already touchy weak layer. Persistent slabs are especially likely at and below treeline. The trees may not be the safe haven you expect: adopt a cautious attitude to all avalanche terrain.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Avoid avalanche terrain around treeline.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 10th, 2018 2:00PM

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