Avalanche Forecast

Issued: Mar 20th, 2013 3:00PM

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

Avalanche Canada pmarshall, Avalanche Canada

Summary

Confidence

Fair

Weather Forecast

Synopsis: A strong low pressure system today with wind and mild temperatures is followed by a cool and unsettled air mass through Friday. Conditions will become gradually less windy and less convective but stay generally cooler than normal for the period. Saturday and Sunday the cool north/northwesterly flow will dry out as a ridge of high pressure is very slowly approaching the regions.Wednesday Night: Freezing Level: Valley Bottom Precip: 10/15mm – 10/25cm Wind: Moderate WestThursday: Freezing Level: 900m Precip: 3/6mm – 5/10cm Wind: Moderate W gusting Strong NW Friday: Freezing Level: 1100m Precip: 3/6mm – 5/10cm Wind: Light gusting strong NorthSaturday: Freezing Level: 800m No significant precip expected.  Wind: Light, North

Avalanche Summary

Tuesday was filled with reports of slufing to size 1 on steep features. In the past few days numerous size 1-2 avalanches have been triggered naturally, by skiers, explosives and vehicles. In most cases, the new snow was failing on the hard (March 16th) crust below. Many were soft slabs where the wind had shifted the snow onto lee slopes, and several were loose dry avalanches.

Snowpack Summary

The KB snowpack structure is a bit complex right now.  Wednesdays storm snow is accumulating on a thin crust that developed on all aspects with the exception of due north on Tuesday.  A thick supportive crust that professionals have dubbed the March 16th crust can be found down 30 - 50 cm.  A buried persistent weakness from March 10th is down approximately 60 cm. This surface hoar/sun-crust combo continues to fail in a sudden planar fashion when tested. Cornices are large and fragile.

Problems

Storm Slabs

An icon showing Storm Slabs
Wednesdays storm snow will be easily transported by forecasted strong W/NW winds Wednesday night into Thursday.  Fresh sensitive wind slabs will be a problem on wind exposed slopes at both alpine and tree line elevations. 
Good day to make conservative terrain choices.>Avoid freshly wind loaded features.>The new snow will require a couple of days to settle out and stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 6

Valid until: Mar 21st, 2013 2:00PM