Avalanche Forecast

Issued: Nov 24th, 2012 12:13PM

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

Parks Canada Danyelle Magnan, Parks Canada

Last weeks storms have improved conditions but there is little snow below 1500m. Recent reports and snowpack test results indicate a great deal of variability. Look for signs of instability and check the snowpack before committing to your line.

Summary

Weather Forecast

Scattered flurries ending this morning as the front continue to move southward. A clearing trend will begin this afternoon as a ridge starts to build. Expect light NW winds and increasing sun over the weekend.

Snowpack Summary

A cohesive storm slab is most reactive where it overlies the Nov 16 sun crust down ~30cm on steep solar aspects in the alpine. The Nov 6 crust is down 80-120cm, with facets forming around the crust. Test results are sudden planar, but hard.

Avalanche Summary

Recent avalanches have been triggered by strong S winds loading lee slopes. Yesterday there were 11 size 2-2.5 slab avalanches from steep north facing terrain. On Thurs there were 2 size 1.5 skier accidental avalanches triggered on the Nov 16 crust.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

An icon showing Storm Slabs
The storm snow is settling into a cohesive slab. It is most reactive on steep solar slopes in the alpine where it overlies a sun crust. Skiers have accidentally triggered avalanches on this layer that have run far and fast.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Assess start zones carefully and use safe travel techniques.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
Strong southerly winds during last weeks storm transported snow, loading lee slopes and forming pockets of windslab. These windslabs may be buried by new snow.
Be cautious as you transition into wind affected terrain.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 - 2

Valid until: Nov 25th, 2012 8:00AM