Avalanche Forecast

Issued: Jan 30th, 2015 7:08AM

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

pgoddard, Avalanche Canada

Cariboos.

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

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Snowfall peters out on Saturday before a second pulse of snow arrives on Sunday and continues through Monday, bringing 10-20 cm. Winds are generally light until Sunday night, when they rise to moderate westerly. Freezing level is at valley floor.

Avalanche Summary

There was a widespread avalanche cycle earlier in the week in response to the warm storm, with a round of persistent slabs. Natural activity has now eased, but a few cornice drops triggered storm slabs on Thursday.

Snowpack Summary

New snow is falling on a supportive crust, found below about 1900 m in the north and 2100 m in the south. At higher elevations, recently formed wind slabs may be found lee to the south-west. Recent warming and subsequent cooling have helped strengthen the mid-January surface hoar layer, but it still remains a concern, especially at high elevations. The mid-December surface hoar layer is 80 to 140cm below the surface and appears to be slowly gaining strength. Basal facets could be triggered with large triggers like cornice fall in specific terrain.

Problems

Wind Slabs

Recent snow and strong winds have left wind slabs and cornices on lee slopes above treeline. These may be hidden by new snow.

Give cornices a wide berth when travelling on or below ridges.>Travel on ridgetops to avoid wind slabs on slopes below.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

A layer of surface hoar buried in the upper snowpack remains a concern, especially at high elevations. An avalanche in motion or cornice fall could also trigger a second, deeper persistent weakness.

Avoid thin or variable snowpack areas that may propagate to deeper instabilities.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Jan 31st, 2015 2:00PM