Avalanche Forecast

Issued: Mar 13th, 2016 10:21AM

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.

Spring "power flurries" may produce more snowfall than forecast. Pay close attention to how much snow falls in your area and select terrain accordingly.

Summary

Confidence

Moderate - Wind effect is extremely variable on Monday

Weather Forecast

On Sunday night and Monday expect 8-10cm of new snow and moderate southwest ridgetop winds. On Tuesday and Wednesday the region should see a mix of sun and cloud with light northwest winds. The freezing level should hover around 1400m for the forecast period.

Avalanche Summary

On Saturday, observations were extremely limited, although I suspect there was some wind slab activity in response to new snow and wind. At the time of publishing on Sunday, there were no new reports of avalanche activity.

Snowpack Summary

On Saturday night around 15cm of new snow fell. The new accumulations were likely shifted into soft wind slabs at treeline and in the alpine by moderate winds. 50-90cm below the surface you'll find a persistent weak layer comprised of surface hoar, facets and/or a thick crust. This layer, which was buried on February 27th, 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

Generally light snowfall on Sunday night and Monday will form new soft slabs at treeline and in the alpine. Watch for triggering in the lee of ridgecrests and terrain breaks

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

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.

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

Aspects: All aspects.

Elevations: All elevations.

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.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 14th, 2016 2:00PM