Avalanche Forecast

Issued: Jan 31st, 2015 8:13AM

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

Avalanche Canada esharp, Avalanche Canada

The chance of triggering a persistent slab has decreased, but the consequences would be high.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

A series of fronts will bring between 10-20 cm of new snow to the southern interior Sunday and Monday before a ridge builds Tuesday with a return to dry conditions.  Winds should be light from the southwest to west.  Freezing levels will remain at valley bottom.

Avalanche Summary

There was a widespread avalanche cycle earlier in the week in response to the warm storm. Natural activity has now eased, but explosives were able to trigger several large slabs (some failing sympathetically with each other) up to size 3 on the January surface hoar layer on Thursday around 2200 m.

Snowpack Summary

New snow overlies variable crusts exist at most elevations, ranging from breakable to supportive. Generally small surface hoar sits on this crust. At the highest elevations, you might find some wind-affected snow and cornices. The mid-January surface hoar remains a concern and can be found down between 30 and 80 cm. In some locations it has reportedly gained quite a bit of strength, but in other spots it still produces sudden (pops) results in snowpack tests. The mid-December surface hoar layer is now 80 to 140cm below the surface and has become unlikely to trigger (but still has the potential for a large avalanche if triggered).

Problems

Persistent Slabs

An icon showing Persistent Slabs
A layer of surface hoar buried in the upper snowpack remains a concern, especially at treeline and higher. A large trigger, like an avalanche in motion or cornice fall, could also trigger a deeper persistent weakness.
Be aware of thin areas that may propagate to deeper instabilities.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Feb 1st, 2015 2:00PM