Avalanche Forecast

Issued: Jan 1st, 2012 9:21AM

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

Avalanche Canada Jlammers, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertainfor the entire period

Weather Forecast

Monday: 10-12cm of snow arriving late in the day / strong southwest winds / freezing level at 1400mTuesday: moderate to heavy snowfall throughout the day / strong southwest winds / freezing level at 1400mWednesday: moderate snowfall / strong south winds / freezing level at 1400m

Avalanche Summary

In the past 24 hours explosives testing in the region produced numerous slab avalanches up to size 2.5 (one of which stepped down to the october crust on a steep, unsupported feature in the alpine. There was also a size 2.5 skier remote (triggered from a distance) avalanche near Pemberton at the 1600m elevation. This avalanche was about 125cm deep and is thought to have ran on the rain crust mentioned in the Snowpack Observations column.

Snowpack Summary

The total snowfall in the past week has amounted to 100-180cm.Weaknesses exist within, and at the base of the storm snow. New and old wind slabs have formed in exposed NW-E facing slopes, 1m deep in some areas. Cornices have grown large and could act as a trigger for large avalanches. Although the break in the weather this weekend has given the upper snowpack some time to stabilize, the avalanche problem in the upper snowpack is still very real and will continue to be with the forecast wind and snow.In the mid snowpack a weak rain crust is found below the new snow up to treeline elevations. This crust, which has recently produced large avalanches, may sit on top of buried surface hoar and/or facets.A strong lower pack contains facets and and an associated crust that have also gained considerable strength.On average the snowpack is around 200cm deep near treeline.

Problems

Wind Slabs

An icon showing Wind Slabs
Deep and dense wind slabs exist below ridge crests, behind terrain features and in cross-loaded gullies. New wind slabs will also form with forecast weather.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Storm Slabs

An icon showing Storm Slabs
Weaknesses within and at the base of the storm snow may be triggered naturally by the weight of a person/sled. Storm slabs could fail on deep persistent weaknesses and at lower elevations than expected.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 5

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