Avalanche Forecast

Issued: Mar 8th, 2017 4:26PM

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

jlammers, Avalanche Canada

Northwest Inland.

Several days of cold benign weather ahead. Concerns include wind slabs at higher elevations and the ongoing potential to trigger deep persistent slabs in shallow snowpack areas.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

Expect a mix of sun and cloud for the forecast period. Ridgetop winds should remain generally light to moderate from the east with alpine temperatures sitting at about -20.

Avalanche Summary

No new avalanches have been reported in the past few days.

Snowpack Summary

Generally light accumulations of low density snow have occurred in recent days. In some areas wind effect at higher elevations has resulted in wind slabs on east and north aspects. About 25cm below the surface, you may find a variety of old snow surfaces including stiff wind slabs, facets, crusts and surface hoar. The new snow may have a poor bond to these interfaces, especially in places where the slab is stiffer and more cohesive due to winds. At treeline, the average snowpack depths are 120-190 cm and a well consolidated mid-pack of approximately up to 100 cm sits above weak basal facets (sugary snow) near the ground. Recent snowpack testing has shown sudden easy results down 25 cm on a surface hoar layer and sudden hard results down 100 cm within the faceted snow.The deeper basal weakness remain a concern, especially in thin rocky start zones and shallow snowpack locations.

Problems

Wind Slabs

Gusty southwest winds at upper elevations have formed fresh wind slabs on leeward slopes and behind terrain features.

Sheltered slopes will likely offer the best skiing today.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

A lingering weakness at the bottom of the snowpack may remain sensitive to human triggering, especially in shallow snowpack areas. Smaller avalanches in motion also have the potential to step down and trigger deep persistent slabs.

Avoid steep convexities or areas with a thin or variable snowpack.Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 9th, 2017 2:00PM