Avalanche Forecast

Issued: Mar 9th, 2014 8:51AM

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

Peter, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Monday: Cloudy with a chance of flurries in the morning followed by a mix of sun and cloud. The freezing level is around 800-1000 m. Winds are moderate from the W-SW. Tuesday: Periods of snow – 5-10 cm. The freezing level is around 1200-1400 m and winds increase to strong from the SW. Wednesday: Periods of snow. The freezing level is around 1000 m. Winds remain strong from the SW.

Avalanche Summary

Numerous natural (to size 2.5) and skier controlled avalanches (to size 2) were reported on Saturday. Most of these released on the recently buried snow surface, but some may have stepped down to the mid February layer. There was also a report of several remotely triggered avalanches.

Snowpack Summary

Around 20-50 cm of dense storm snow now sits on a layer of surface hoar and/or a thick layer of facetted snow on shady slopes at all elevations, a sun crust on steep solar aspects, and various wind affected surfaces in exposed terrain. Strong southwest winds have created dense wind slabs on exposed lee slopes and in cross-loaded features. The early February weak layer of facets, crusts, and surface hoar is buried down about 70-120 cm. There is no new info on this weak layer, but I suspect it remains active in many areas. Basal facets and depth hoar remain a concern in areas with thin or variable snow cover.

Problems

Storm Slabs

Up to 50 cm of dense storm snow overlies the previous snow surface of weak sugary facets, old wind slabs, or a melt-freeze crust. Triggering is more likely on steep unsupported or convex shaped slopes and in wind loaded N to E aspects.

Avoid freshly wind loaded features.>Use conservative route selection, stick to moderate angled terrain with low consequence.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Persistent Slabs

A weak layer buried in mid-February is now down 60-120 cm deep. Triggering an avalanche on this layer would result in a very large and destructive avalanche.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 10th, 2014 2:00PM