Avalanche Forecast

Issued: Mar 12th, 2016 7:34AM

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

jlammers, Avalanche Canada

Cariboos.

Although persistent weak layers have become less likely to trigger, the consequences of an avalanche could be high. Conservative terrain selection is highly recommended.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

Saturday night: 5-8cm of new snow / Strong southwest ridgetop winds / Freezing level at about 1500mSunday: Light flurries with possible sunny breaks / Light to moderate ridgetop winds / Freezing level at about 1000mMonday: 8-12cm of snow / Moderate easterly ridgetop winds / Freezing level at about 1000mTuesday: Mix of sun and cloud / Light ridgetop winds / Freezing level at about 1000m

Avalanche Summary

On Friday there was widespread evidence of natural storm slab activity to size 2.5. These avalanches likely occurred during Thursday's storm. A few wind slabs to size 1.5 were also ski cut on Friday.

Snowpack Summary

At treeline and in the alpine, light snow accumulations overlie wind slabs which formed during Thursday`s storm. 50-90cm below the surface you'll find a persistent weak layer comprised of surface hoar, facets and/or a thick crust. This layers seems variably reactive. In other words, it's still really touchy in some places while in other places it's really tough to trigger, and there's not much of a reliable pattern telling us what exact aspects are most suspect. I'd continue to be suspicious of steep, unsupported features at treeline and in the alpine as this layer has the potential for very large avalanches. Below this interface, the snowpack is generally gaining strength. At ridgetop, cornices are huge and potentially unstable.

Problems

Wind Slabs

New snow and wind will form new wind slabs in upper elevation lee terrain. The new snow may also be hiding older, larger wind slabs which formed on Thursday.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

A persistent weakness lies buried up to 90cm below the surface. Although this layer is slowly becoming less likely to trigger, it has the potential to surprise with nasty consequences. I'd continue riding with a conservative mind set.

Choose well supported terrain without convexities.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Cornices

Large cornices loom over open bowls and alpine faces. Not only are massive cornice falls a hazard in themselves, but they can also act as a heavy trigger for slab avalanches on the slope below.

Extra caution needed around cornices with current conditions.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 13th, 2016 3:00PM