Avalanche Forecast

Issued: Mar 29th, 2015 8:39AM

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

pgoddard, Avalanche Canada

Cariboos.

Snowfall amounts are highly variable. In some parts of the region, danger may be HIGH in the alpine.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Snow eases to light amounts on Monday, then the next pulse begins on Monday night, bringing around 5-15 cm snow with moderate to strong SW to NW winds. Freezing levels peak around 2200 m on Monday afternoon, then drop on Tuesday to around 1500 m.

Avalanche Summary

A natural avalanche cycle, size 2-3, was observed on Friday and Saturday. These were slabs up to 100 cm deep and loose wet avalanches on all aspects.

Snowpack Summary

Strong winds have shifted snow onto lee slopes at high elevations. Cornices are large and fragile. Rain below treeline is saturating the snowpack. In the alpine and at treeline, two persistent weak layers in the upper metre or so of the snowpack are the main story. The mid-March layer, around 60 cm down, is most reactive where it exists as a crust. Around 80-100 cm down, the mid-February facet/crust interface has also been reactive. Both layers (or facets in between the two layers) are sensitive to triggering and propagate easily, causing very large avalanches. As temperatures rise on Monday, the reactivity of storm slabs and persistent slabs may go up.

Problems

Storm Slabs

New snow and winds are likely to create touchy storm slabs, especially on features in the lee of the wind. At low elevations, loose wet avalanches may be running.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid freshly wind loaded features.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

Persistent slabs are touchy and may be triggered naturally, or with the weight of a sledder or skier.

Choose conservative lines and only group up in safe terrain away from avalanche runouts.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

3 - 6

Valid until: Mar 30th, 2015 2:00PM