Avalanche Forecast

Issued: Dec 10th, 2012 3:00PM

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.

Alberta Parks burke.duncan, Alberta Parks

Winds and wind loading remain the primary concern at and above treeline. As these slabs build they become more sensitive to human triggering.  Current forecasts do not show much more than few centimeters of new snow over the next few days.

Summary

Confidence

Good

Weather Forecast

A relatively warm, moist NW upper air flow has been producing some light flurries  in areas close to the divide. A colder air mass is trailing behind the current warm front and temps will gradually decline over the next 24-48 hours.  Little new precipitation is expected.

Avalanche Summary

Only a few natural, loose, dry sluffs up to Size 1 have been observed in the past 24 hours although visibility was limited at times.

Snowpack Summary

Minimal (1cm) new snow over the previous 24 hours.  A strong temperature gradient is resulting in increased facetting and progressive weakening within the snowpack.  A W-NW flow through day is contributing toward additional redistribution of storm snow at and above treeline.

Problems

Wind Slabs

An icon showing Wind Slabs
Watch for pockets of these wind slabs along ridgelines, around cross loaded features and be especially careful around unsupported terrain. Ski cutting produced small avalanches over the past 48 hours and additional winds will make these slabs bigger.
Avoid convexities or areas with a thin or variable snowpack.>Avoid cross loaded features.>Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
The Nov rain crust persists about 30+cm off the ground throughout the forecast area and is reactive to stability tests in the hard range. Avalanches in the upper snowpack may step down to this weakness.
Assess start zones carefully and use safe travel techniques.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 11th, 2012 2:00PM