Avalanche Forecast

Issued: Feb 23rd, 2013 8:55AM

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

Peter, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Synopsis: The active weather pattern continues into next week with a series of frontal systems affecting the region with short breaks in between each pulse.Sunday: Snow beginning during the day – around 10 cm. The freezing level is around 1000 m and winds are moderate from the southwest. Monday: Snow should continue for most of the day with an additional 10-15 cm possible. The freezing level should drop down to near valley bottom. Tuesday: A drier day as a brief ridge of high pressure forms. Temperatures remain steady and winds are light.

Avalanche Summary

There were no new reports of avalanches on Friday, but this was probably due to poor weather and few observers in the field and not lack of activity. Just to the southeast, in the North Monashees and Selkirks, there was a fairly widespread natural avalanche cycle in response to heavy snow and strong wind on Friday.

Snowpack Summary

30-50 cm of new snow has fallen in the past 2 days. Strong west-southwest winds have redistributed the new snow into deep wind slabs on exposed lee slopes and cross-loaded gully features. The February 12 persistent weak layer (crust, and/or surface hoar) is now down 60-80 cm and is primed for triggering. Recent snowpack tests have shown easy to moderate "pops" results on this interface. Deeper persistent weak layers from early February and late January continue to show planar failures when moderate to hard forces are applied in snow pack tests. These deeper layers have not been reactive to the weight of a rider, but they may be triggered by large loads like an avalanche in motion (step-down avalanche), or a cornice fall.

Problems

Storm Slabs

Weaknesses may exist within the storm snow and may be triggered by additional loading. Expect deep and dense wind slabs in exposed north through southeast facing terrain.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Stick to non-avalanche terrain or small features with limited consequence.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

Additional loading from snow and wind, or the weight of a rider could be enough to trigger the February 12 persistent weak layer.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 6

Valid until: Feb 24th, 2013 2:00PM