Avalanche Forecast

Issued: Jan 30th, 2012 9:43AM

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 ccampbell, Avalanche Canada

Summary

Confidence

Fair - Due to limited field observations for the entire period

Weather Forecast

A zonal flow is forecast through Wednesday with moderate to strong westerly winds and short-lived disturbances delivering 5 to 10 cm of snow each day, especially on the west (upslope) side of the ranges. Freezing level should remain near valley bottoms. Heavier precipitation is expected to start Wednesday evening when the next major system hits the coast which could bring another 30+cm by Thursday evening with freezing levels as high as 1200m.

Avalanche Summary

Reports are coming in about a widespread natural avalanche cycle that occurred on Saturday with avalanches up to Size 3.5 running almost full-path on all aspects and elevations. Natural and slope-cut activity continued on Sunday with avalanches up to Size 2 running within the upper storm snow on steep unsupported features and gullies at treeline and below. Explosive control on Sunday produced avalanches up to Size 3.5 all running on weaknesses within the recent storm snow.

Snowpack Summary

Total snowpack depths are well above average for this time of year and it won't stop snowing!Recent warm temperatures and upside-down storms created a touchy surface slab. Other weaknesses exist within and under the 150+cm of recent storm snow, but things seem so be settling rapidly. Strong winds associated with recent storms mean wind slabs on lee and cross-loaded terrain. Most snowpack concerns are limited to the surface layers, however large triggers such as cornice falls and smaller avalanche stepping-down could reawaken deeper persistent weaknesses.

Problems

Wind Slabs

An icon showing Wind Slabs
Widespread due to strong, shifting winds and large amounts of snow available for transport, but are generally lurking below ridgecrests, behind terrain features and in cross-loaded gullies. They can fail as very large, destructive avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 6

Storm Slabs

An icon showing Storm Slabs
Large storm slab avalanches have been occurring for the past week and are expected to remain sensitive to triggers for the forecast period.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 6

Valid until: Jan 31st, 2012 8:00AM