Avalanche Forecast

Issued: Mar 3rd, 2016 8:38AM

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

jlammers, Avalanche Canada

Northwest Inland.

New snowfall amounts are uncertain for Thursday night. Pay close attention to how much snow falls in your riding area, and be prepared to back off to conservative terrain.

Summary

Confidence

Low - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

Weather models are calling for up to 15cm of new snow on Thursday night withÂ another 10cm of new snow on Friday evening. Generally light flurries are forecast for Saturday while a mix of sun and cloud is expected on Sunday. Ridgetop winds on Friday will be strong from the south, becoming light on Saturday and Sunday. Freezing levels will hover around 1200m on Friday and then rise to about 1400m for the weekend.

Avalanche Summary

On Wednesday, a size 3 deep persistent slab avalanche was accidentally triggered by a skier in alpine terrain in the north of the region. To our knowledge, nobody was injured in the incident. The slab, which ran on basal facets, was up to 200cm deep, 200m wide and 500m long. There have been a handful of recent similar avalanches triggered on basal facets in the mountains north of Kispiox. Although observations have been limited, I suspect new snow and wind on Wednesday night also promoted a round of wind slab activity at treeline and in the alpine.

Snowpack Summary

On Wednesday night 5-15cm of new snow fell. Much of this new snow was likely shifted by strong winds into new wind slabs in exposed lee terrain. A layer of surface hoar from early January can be found in isolated locations between 60 and 140cm down. There hasn't been any activity reported on this layer for a couple of weeks now and it is becoming less of a concern. The snowpack in shallower areas sits on a weak base layer of facetted snow. Recently, this layer has been active in the north of the region, responsible for several large avalanches in unsupported alpine terrain.

Problems

Wind Slabs

New snow and wind will create fresh wind slabs at treeline and in the alpine. Watch for triggering in the lee of ridgecrests and terrain breaks.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

A layer of facets close to the ground remains a low probability/high consequence concern for most of the region. However, in the north it is more active and has been responsible for several recent large natural and skier triggered avalanches.

Be aware of thin areas that may propogate to deeper instabilites.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Mar 4th, 2016 2:00PM