Avalanche Forecast

Issued: Mar 31st, 2014 9:56AM

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

mbender, Avalanche Canada

Purcells.

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Tuesday: Mostly sunny. Freezing level 1600m. Winds west and northwest light.Wednesday: Mix of sun and cloud. Freezing level 1600m. Light west winds.Thursday: Cloudy with sunny periods. Winds light south. Freezing level 1700m.

Avalanche Summary

Recent reports indicate are limited to loose dry and moist snow avalanches running in steep terrain in the alpine and at tree-line. Expect to see natural avalanche activity rise with extended periods of sun and an increase in air temperatures later in the week.

Snowpack Summary

Up to 50cm of new snow has fallen in the central part of the region in the last 3 days (5-10cm in the northern part of the region). This new snow is settling and being formed into soft wind slabs immediately lee of ridge crests recent westerly winds.Numerous crusts can be found in the upper 60cm of the snowpack on south facing slopes. The March 15 crust/surface hoar interface is down 50-80cm. Down 90-120cm below the surface you may find surface hoar and crusts buried at the beginning of March. This interface is still touchy in some areas, particularly in the north of the region. It also continues to produce sudden planar failures in compression tests.The deeper facet/crust persistent weakness buried at the beginning of February, now down 120 - 200cm, still seems to be reactive and should not be trusted. Needless to say, any avalanche at these deeper, persistent interfaces would be large and destructive. Weak basal facets exist in many areas, but without a large load, triggering is unlikely.

Problems

Wind Slabs

Recent accumulations have likely been blown into pockets of wind slab by generally west winds.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>Stay well to the windward side of corniced ridges.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

There are a number of persistent layers in the mid to lower snowpack which have professional operators concerned. Possible triggers include cornice fall, thin spot triggering and/or solar warming.

Be aware of the potential for large, deep avalanches.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Apr 1st, 2014 2:00PM