Avalanche Forecast

Issued: Apr 1st, 2015 8:02AM

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

danyelle magnan, Parks Canada

Glacier.

A cooling trend is helping to lower avalanche danger but have also brought a return to more wintery problems at higher elevations. New snow, sustained winds, and persistent weak layers mean that there are lots of factors to keep in mind to stay safe.

Summary

Weather Forecast

Today will remain unsettled with convective flurries and potentially some sunny breaks. Moderate, but gusting to strong, westerly winds will be transporting the new snow building cornices and loading lee slopes. Thursday should be dry with a mix of sun and cloud. Alpine temps will reach -4'C. On Friday expect flurries and SW winds.

Snowpack Summary

Temps cooled off overnight, and at 1300m 3cm of snow overlies a 3cm thick crust. At 1900m ~20cm of dry snow overlies 30cm of heavy wet snow at treeline. This adds to the load sitting on a series of crust layers. Snowpack tests indicate that these layers may be triggerable by light loads, and if triggered are capable of propagating widely.

Avalanche Summary

Numerous size 2-3, loose wet avalanches were observed along the highway corridor. Avalanche activity tapered off in the afternoon as temps cooled, precipitation rates decreased and winds died down.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Storm Slabs

20cm of new snow has added to the growing storm slabs at higher elevations. Strong SW'ly winds have magnified loading creating deeper, and touchier, pockets in lee areas. The storm slabs may be more reactive where they bond poorly to crusts below.

Avoid freshly wind loaded features.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

A series of weak layers in the top 1.5m of the snowpack are more easily triggered due to the load added by the new snow and rain over the past week. They may be triggered by the added load of a person, another avalanche or a cornice falling.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 2nd, 2015 8:00AM