Avalanche Forecast

Issued: Jan 5th, 2012 9:25AM

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

ccampbell, Avalanche Canada

South Coast.

Summary

Confidence

Good - -1

Weather Forecast

Friday: Dry with increasing cloud cover and flurries possible in the evening. Freezing levels in valley bottoms and light winds. Saturday: Cloudy but dry with moderate precipitation starting in the evening. Freezing levels are expected to rise to 1300m and southwesterly winds increase to moderate with the onset of precipitation. Sunday: Isolated moderate snow flurries with strong southwesterly winds.

Avalanche Summary

Widespread natural avalanche activity up to Size 3 was reported on Wednesday. Fresh storm and wind slabs, as well as deeply buried persistent slabs remain sensitive to human triggers.

Snowpack Summary

Weaknesses within and under the 60-100+cm of storm snow will need some time to settle and strengthen. Persistent weaknesses remain a concern in the northern part of the region. Buried surface hoar on sheltered treeline slopes and below and facets with associated crusts in exposed treeline and alpine areas are probably down well over a metre in most places, and facets lurk near the base of the snowpack in shallow rocky areas. Wind-loading has resulted in highly variable slab thicknesses with the potential for fractures triggered in highly sensitive thin slab areas to propagate into highly destructive deep slab avalanches. Furthermore, weaknesses within the slab create the potential for step-down fractures.

Problems

Wind Slabs

Watch for sensitive wind slabs lurking below ridgecrests, behind terrain features and in cross-loaded gullies.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Storm Slabs

Watch for touchy storm slabs on steep unsupported terrain features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Persistent Slabs

Primarily a concern in the northern part of the region. Especially easy to trigger from thin slab areas, or from storm or wind slab avalanches stepping down to deeper weaknesses.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Jan 6th, 2012 8:00AM