Avalanche Forecast

Issued: Jan 16th, 2012 9:49AM

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 ccampbell, Avalanche Canada

Summary

Confidence

Poor - Track of incoming weather is uncertain on Wednesday

Weather Forecast

Tuesday: Continued isolated flurries with freezing levels in valley bottoms and strong westerly alpine winds. There is high uncertainty with the weather for Wednesday and Thursday. Some forecast models are calling for moderate snowfall while others are calling for almost none. It all has to do with track of a frontal system that's primarily heading south of the region. If heavy loading from snow or wind does occur, then expect avalanche danger to increase.

Avalanche Summary

Reports from yesterday include isolated Size 1 human triggered wind slab avalanche on a east-northeast facing alpine slope near the ridgecrest, generally sluggish and slow moving. Low density storm snow is sluffing readily in steep terrain with a natural cycle overnight Saturday. In some cases they're entraining considerable mass and reaching up to Size 2.

Snowpack Summary

Snow flurries have maintained a fresh snow supply for wind slab development and cornice growth, but remains fluffy and cohesionless in most sheltered areas. Surface hoar and/or faceted snow, with an associated crust making it especially touchy on sun-exposed slopes, was buried last week and is now down 15-25cm. Below that a thin melt/freeze crust buried early-January can be found as high as 1900m, and some areas are reporting surface hoar . The mid-December surface hoar/facet persistent weakness, now down 50-120cm, remains a concern with heavy triggers in thin slab areas. Basal facets remain concern in shallow snowpack areas especially with heavy triggers in thin spots, and weaknesses in the slab above create the potential for step-down avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh weak wind slabs are lurking below ridgecrests, behind terrain features and in cross-loaded gullies.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
Weak surface hoar is primarily a concern on big unsupported sheltered glades on east through north aspects. Basal depth hoar and facets are a concern on slopes with shallow and variable snowpack depths, especially near ridges and summits.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Jan 17th, 2012 8:00AM

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