Avalanche Forecast

Issued: Dec 5th, 2013 8:02AM

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

danyelle magnan, Parks Canada

Glacier.

Summary

Weather Forecast

The arctic air is going to continue to dominate bringing cold, dry and mostly sunny conditions. The alpine temps today should range from -19 to -25 with light NE winds. Friday should be -25 to -30 with light E winds. On Saturday we should temps of -20 to -25 with moderate N winds.

Snowpack Summary

Surface facetting is softening windslabs and new surface hoar growth is occurring. The November 28 surface hoar/crust interface is down 30-40 and the November 12 surface hoar layer is down 60-110cm.

Avalanche Summary

No new natural avalanches were observed yesterday. On Tuesday, a group reported easily ski cutting a few pockets of soft windslab in 8812 bowl. Earlier in the week, several large avalanches natural avalanches occurred. They all appeared to be 30-40cm deep, likely on the Nov 28 surface hoar/crust.

Confidence

Problems

Wind Slabs

Strong southerly winds earlier this week, shifted to strong northerly before dropping off. Widespread wind transport created windslabs on all aspects. They likely exist in unusual areas due to the reverse loading and may catch you by surprise.

Be cautious as you transition into wind affected terrain.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

A variety of weak surfaces, including widespread surface hoar and sun crust on steep solar aspects, make this persistent slab tricky. It may be stubborn to trigger but recent avalanches on this layer have been large and propagated widely.

Dig down to find and test weak layers before committing to a line.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 6th, 2013 8:00AM