Avalanche Forecast

Issued: Feb 8th, 2012 9:27AM

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

Avalanche Canada ccampbell, Avalanche Canada

Summary

Confidence

Good - -1

Weather Forecast

A series of weak frontal systems are expected to bring 3-10cm to the region each day and particularly Thursday afternoon, but the timing is uncertain. Winds are expected to be generally light southwesterlies, but winds associated with snow squalls could get quite gusty. Freezing levels could reach as high as 1500m with the passage of warm fronts.

Avalanche Summary

Fresh hard wind slabs on west through northeast aspects are very touchy with natural and skier-triggered avalanches up to size 2. Loose faceted surface snow is sluffing readily in steep terrain and gaining considerable mass. Check out the incident database (under the Bulletins tab) for reports of recent avalanche involvements in the region, and search vimeo.com for helmet-cam footage of the Feb. 3rd incident near Nelson.

Snowpack Summary

The current snow surface is well on its way in becoming a dangerous weak layer once a sufficiently cohesive slab develops. Surface hoar is continuing to develop on sheltered slopes at all elevations combined with near-surface facets at lower elevations and surface crusts on sun-exposed slopes. There is still dry snow on northerly aspects at higher elevations, but it is likely wind-affected and variable in exposed areas. Concerns remain for the mid-December surface hoar layer. Basal facets were recently responsible for a large whumpf on a shallow south facing treeline slope in the Rossland Range and gave very easy and sudden compression tests results where they were found down 60cm.

Problems

Wind Slabs

An icon showing Wind Slabs
Weak wind slabs could be lurking below ridge crests and behind terrain breaks. Watch for reverse-loading from easterly winds, and highly variable cross-loaded slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Very large avalanches remain a concern in shallow rocky areas with heavy triggers, such as cornice falls and step-down avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Feb 9th, 2012 8:00AM

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