Avalanche Forecast

Issued: Jan 5th, 2012 8:13AM

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

jfloyer, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

The region will stay mostly dry on Friday with freezing levels remaining at valley bottom. Expect moderate westerly winds. Over the weekend, a storm system will bring around 10 cm new snow on Saturday and 15-20 cm on Sunday. Freezing levels will go up to around 600 m on Saturday and could go up to 1500 m on Sunday. Winds will continue to be strong from the southwest.

Avalanche Summary

A natural avalanche cycle up to size 2 was reported from the region affecting all aspects. Avalanches were initiating in the storm snow.

Snowpack Summary

New snow and strong winds have set up fresh wind slabs at higher elevations, mainly on north through east aspects in exposed lee terrain--these are likely triggerable by riders on sleds or on skis. Lower down, a rain crust exists up to approximately 1000 m. There is now approximately 80 to 120cms of storm snow sitting above a surface hoar/crust/facet layer that was buried mid-December. The increasing depth of this weak layer makes it difficult to trigger; however, I wouldn't ignore this layer yet, as it could still be triggered by large loads such as rapid loading by new snow or rain or cornice falls. It could also be triggered by riders in shallow snowpack areas or where rocks poke up near the surface. The mid- and lower snowpack layers are well consolidated and generally strong.

Problems

Wind Slabs

Strong southwesterly winds have set up touchy wind slabs on mainly north through east aspects.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 6

Storm Slabs

New snow with rising temperatures has set up storm slabs on steep, open slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 5

Persistent Slabs

Persistent slabs are getting harder to trigger but still exist in many locations. The probability of triggering has decreased, but the consequences of a release remain high.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 6

Valid until: Jan 6th, 2012 8:00AM