Avalanche Forecast

Issued: Dec 3rd, 2014 4:00PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

Human triggered avalanches are still likely due to the instability of recent storm snow sitting over the basal rain crust/facets. This will not change in the short term. SH

Summary

Weather Forecast

A warming trend Thursday with daytime highs in the -5 to -10 range. No snow is expected on Thursday, and light snow amounts of 5-10cm are forecast for Friday and Saturday. Light to moderate SW winds for the next few days.

Snowpack Summary

Recent storm snow has settled into a soft slab and has significant wind affect in open terrain at treeline and above. The lower half of the snowpack is complex and poorly structured & comprised of the facets (Nov 24th) at the interface of the recent storm snow and a series of thin crusts (Nov 6th) and depth hoar at or slightly above the ground.

Avalanche Summary

No new activity reported, but a natural 2.5 in the Sunshine backcountry yesterday triggered by wind loading shows large natural avalanches are still possible at higher elevations.

Confidence

Due to the number of field observations on Thursday

Problems

Deep Persistent Slabs

The primary problem in the snowpack is the interface between the recent storm snow and the November 6th and 24th facet/crust interfaces. This is the problem responsible for the majority of the avalanches in the past week. Watch for remote triggers.

Watch for whumpfing, hollow sounds, and shooting cracks.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Many places have been ravaged by winds from many directions, especially in the alpine. Watch for pockets of hard slab near ridge tops and cross loaded features..

Watch for whumpfing, hollow sounds, and shooting cracks.Be careful with wind loaded pockets while approaching and climbing ice routes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 2

Valid until: Dec 4th, 2014 4:00PM