Avalanche Forecast

Issued: Jan 1st, 2012 9:25AM

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

Avalanche Canada Jlammers, Avalanche Canada

Summary

Confidence

Fair - Freezing levels are uncertainfor the entire period

Weather Forecast

Monday: 5-7cm of snow arriving late in the day / moderate to strong southwest winds / freezing level at 1400mTuesday: Light to moderate snowfall throughout the day / strong southwest winds / freezing level at 1400mWednesday: moderate to heavy snowfall / strong south winds / freezing level at 1400m

Avalanche Summary

No new avalanches were reported in the past 24 hours.

Snowpack Summary

The past week's storm snow totals are now in the 60-90cm range. Strong southerly winds shifted snow into wind slabs on lee slopes in the alpine and at treeline. The past weekend saw a break in the weather and the upper snowpack may have strengthened, but only marginally. Expect further wind and storm slab development throughout the forecast period.Below the recent storm snow, three weaknesses exist in the mid snowpack. A surface hoar layer formed in early December overlies facets and is down about 60cm. It is giving easy, sudden collapse results in snowpack tests.A second surface hoar layer buried around Christmas is also giving easy, sudden planar results.A crust/facet combo which exists to around treeline, buried on December 17th, adds to the complexity of the snowpack and has shown the potential to propagate widely.Persistent weaknesses seem to be more of a concern around the Duffey Lake area than in the Cascades (Coquihalla and Allison Pass).The lower snowpack is generally well-settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
Be alert for ongoing wind slab development in lee and cross-loaded terrain. Be aware of cornice development at ridgecrests.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Buried weaknesses in the mid to upper snowpack have created an avalanche problem which may be triggered by people or by additional wind-loading. There is potential for surprisingly large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Valid until: Jan 2nd, 2012 8:00AM