Avalanche Forecast

Issued: Feb 25th, 2018 3:33PM

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

Avalanche Canada pgoddard, Avalanche Canada

Recent snow will need time to stabilize and ongoing winds are likely to drive continued wind slab development.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

MONDAY: Mix of sun and cloud. Freezing level near 600 m. Moderate westerly winds. TUESDAY: Mix of sun and cloud with flurries. Freezing level near 900 m. Moderate south-westerly winds.WEDNESDAY: Mix of sun and cloud with flurries. Freezing level near 900 m. Moderate south-westerly winds.More details can be found in the Mountain Weather Forecast.

Avalanche Summary

A skier triggered a size 2 slab on a steep south-east facing slope near ridge crest at 1970 m on Saturday. It was 20-60 cm deep and failed on facets. Explosives testing produced several loose dry avalanches in steep terrain. A natural cornice fall triggered a size 2 wind slab on a north-east aspect.A skier also remotely triggered a size 2 persistent slab on a north aspect at 1750 m. It failed on surface hoar, which is isolated in its distribution, but is most likely found on sheltered north aspects.A developing wind slab problem was observed as winds picked up throughout the day. These problems are expected to continue to develop, and may be especially touchy in specific locations where they overlie buried persistent weak layers.

Snowpack Summary

New wind slabs are building quickly as available light dry snow is moved around by moderate to strong winds. Snow spillage from steep ground is also loading up fans. In more sheltered locations, you may encounter storm slabs or loose dry sluffing. These upper snowpack problems overlie various old surfaces including old hard wind slabs, crusts, facets and spotty surface hoar. Deeper in the snowpack, the widespread mid-December weak layer sits about 130-220 cm deep. This consists of a crust, facets or surface hoar. Near the base of the snowpack, a crust/facet layer could be awoken from a thin-spot trigger point, or with a very large load like a cornice fall.

Problems

Wind Slabs

An icon showing Wind Slabs
Touchy wind slabs can be found near ridges and ribs.
Be cautious as you transition into wind affected terrain.Minimize exposure to overhead hazard from cornices.Travel on ridgetops to avoid wind slabs on slopes below.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Storm Slabs

An icon showing Storm Slabs
Storm snow will be especially sensitive to human triggers in steep or convex terrain.
Choose conservative lines and watch for clues of instability.Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.Avoid travelling on ledges and cliffs where sluffing may have severe consequences.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Valid until: Feb 26th, 2018 2:00PM

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