Avalanche Forecast

Issued: Feb 5th, 2017 3:47PM

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

Avalanche Canada mgrist, Avalanche Canada

Touchy wind slabs are the main concern at treeline and above. The avalanche danger may be higher in the north of the region where very large, full depth avalanches remain a concern.

Summary

Confidence

Moderate - The weather pattern is stable

Weather Forecast

Steady weather pattern for the Northwest: Cool and mostly clear, moderate outflow winds.MONDAY: Mix of sun and cloud / Moderate to strong east wind / Alpine temperature -14TUESDAY: Sunny / Moderate east wind / Alpine temperature -14WEDNESDAY: Sunny / Moderate east wind / Alpine temperature -15

Avalanche Summary

Size 2 wind slabs were remotely triggered the south Douglas zone on Saturday, releasing from shallow cross-loaded gullies. Several natural avalanches to Size 2.5 were observed in lee alpine features on Friday near Shames ski hill. (Hard) wind slabs were reactive even on small, relatively low angled slopes at treeline in the same area. In the northern most parts of the region near Bell2 or Ningunsaw there are still reports of natural and skier triggered avalanches to Size 2.5 stepping down to basal facets in the alpine and tree line.

Snowpack Summary

The snow from last week has been redistributed by continuous strong to extreme (north) easterly outflow winds, creating widespread wind effect. Touchy wind slabs on south/southwest aspects up to 45cm thick were running on relatively low angled terrain near 1300m in the Shames backcountry. At lower elevations, precipitation fell as rain and a surface (or near-surface) crust may now be found below about 1000m. Below the recent storm snow the January 18th rain crust is producing moderate sudden shears down 85cm in snowpack tests; however, it isn't showing signs of propagation being likely. The snowpack below this is generally strong and well settled. The exceptions are areas around Bear Pass and Ningunsaw where basal facets (under wind slab) remain an ongoing concern, especially in shallow snowpack areas.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent strong wind has created wind slabs in alpine and tree line lees. Surface avalanches may also step down to deeper, more destructive layers.
Be cautious as you transition into wind affected terrain.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
In the north of the region, full depth avalanches continue to fail on weak layers at the base of the snowpack.
Dig down to find and test weak layers before committing to a line.Be aware of the potential for wide propagations due to the presence of buried surface hoar layers.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Feb 6th, 2017 2:00PM

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