Avalanche Forecast

Issued: Dec 26th, 2011 9:19AM

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

swerner, Avalanche Canada

South Rockies.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Over the forecast period a series of fronts will pass through the interior. They'll bring strong south westerly winds, accompanied by rising freezing levels and new snow. Meteorologists find it tricky to pinpoint the timing of each storm when they are embedded in a strong zonal flow. They are confident in the pattern every (18-24hrs) per system but less confident in timing, and intensity.Tuesday: Snow amounts 5-10cm. Westerly winds 65-95km/hr. Max temperature at 1500m -2. Wednesday: Snow amounts 5cms. Strong westerly winds up to 80km/hr. Freezing levels could rise to 1600m steady into Thursday. Thursday: Light snow amounts. Freezing levels should fall 1000m or less.

Avalanche Summary

No new avalanches. Nearby (in the Lizard Range) there were 2 incidents reported on December 22 and 1 on December 23. For more information please visit avalanche.ca, click Bulletins then incident report database.

Snowpack Summary

Westerly winds continue, creating wind slabs on lee locations in the alpine and open treeline. A buried layer of surface hoar lies approximately 20 cm below the snow surface. Reports indicate this layer was blown around before it was buried and can only be found in isolated, sheltered locations at and below treeline. A well settled mid pack bridges over the basal weaknesses at the ground.

Problems

Wind Slabs

Predominantly north through southeast but cross-loading is also possible on open slopes oriented parallel to the wind, which contain features and gullies to catch wind-drifted snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

More of an issue in the northern part of the region where the snowpack is deeper. The mid-December surface hoar layer was destroyed in wind exposed areas. I'd be suspicious of sheltered treeline locations where it may be more preserved.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 27th, 2011 8:00AM