Avalanche Forecast

Issued: Mar 15th, 2013 9:20AM

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

Avalanche Canada ghelgeson, Avalanche Canada

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Synopsis:  The pattern calms down a bit becoming drier and colder, although most of the Arctic Air should flush out by Sunday.Saturday:  Freezing Level: 400m Precip: 2-6mm/5-10cm Wind: W, Light gusting Moderate+.Sunday:  Freezing Level: 200m Precip: trace Wind: W, LightMonday: Freezing Level: 300m Precip: 5mm/5-10cm Wind: E, Light

Avalanche Summary

A bit of sluffing from steep terrain was reported Thursday along with a natural size 1 avalanche from a wind loaded pocket below a small cornice that failed on the March 9th surface hoar.  In the southern portion of the region a couple large glide slabs failed resulting in large (size 3) avalanches.

Snowpack Summary

30 - 60cm of unconsolidated storm snow rests on the old/new snow interface.  Prior to this last storm, the surface was a mix of crusts, old wind slabs and fairly widespread large surface hoar (which we're calling the March 9th surface hoar).  Professionals in the region are keeping their eyes on this layer and testing produces sudden collapse failures at this interface.  In many places, the storm snow has not yet taken on any slab characteristics, but there are no doubt some locations where the storm snow has been massaged into a more cohesive slab.  As a result the current slab problem is "pockety" in nature.  You'll need to dig down to the old surface and test it to get a feel for what's happening in your particular drainage.  The mid snowpack is generally well settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
Pockets of wind slab exist on wind exposed features.  This problem is most prevalent on steep wind exposed features in the alpine and unsupported/convex slopes at all elevations.
Choose conservative lines and watch for clues of instability.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 5

Valid until: Mar 16th, 2013 2:00PM

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