Avalanche Forecast

Issued: Dec 23rd, 2011 8:49AM

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 jlammers, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertainfor the entire period

Weather Forecast

Saturday: 3-5cm of snow - moderate to strong southwest winds - Freezing level at 1200mSunday: 8-12cm of snow arriving late in the day - moderate southwest winds - freezing level at 800mMonday: 8-12cm of snow - light to moderate southwest winds - freezing level at surface

Avalanche Summary

Fresh wind slabs and cornices are sensitive to human-triggers A size 2 windslab was ski cut yesterday on Vantage Peak on the Duffey Lake area (alpine elevation band-northeast aspect)

Snowpack Summary

Dribs and drabs of new snow, in the Coquihalla area, with associated winds are keeping wind slabs fresh and poorly bonded, but also keeping recent surface hoar development and distribution to a minimum. While in the Duffey Lake area, wind-exposed slopes are predominately scoured and pressed, with pockets of hard wind slab. Buried surface hoar and/or facets persists 10 or so centimetres below a weak rain crust on sheltered treeline slopes and below, where recent compression tests on a northerly aspect at 1750m produced easy sudden results down 20cm on surface hoar as large as 15mm. The mid and lower snowpack are generally well-settled and strong, but recent reports suggest basal facets create a deep persistent slab problem that deserves caution in shallow snowpack areas on planar rocky slopes.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs have developed on lee and cross-loaded terrain in the alpine and at treeline. Rider triggered wind slabs are likely.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Storm slabs have now formed at all elevations. They may be developing into a more persistent problem where the mid December buried surface hoar/crust/facet layers exist.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Dec 24th, 2011 8:00AM

Login