Avalanche Forecast

Issued: Mar 8th, 2016 7:44AM

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

pmarshall, Avalanche Canada

Northwest Inland.

Danger may be moderate, but keep the lurking deep persistent slab problem in the back of your mind. Avoid shallow and variable snowpack areas and slopes prone to large triggers like cornices.

Summary

Confidence

Moderate

Weather Forecast

WEDNESDAY: Cloudy with flurries and sunny breaks. The freezing level gradually climbs to 1200 m. Ridge winds are light increasing to strong from the SE. THURSDAY: Periods of snow -10-15 cm. The freezing level is near 1500 m and winds are moderate from the E-SE. FRIDAY: A mix of sun and cloud. The freezing level is around 1200-1400 m and winds ease to light.

Avalanche Summary

A couple natural size 2 wind slabs were observed on immediate lee alpine slopes on Monday. One size 3 natural storm slab was observed in the Southwest corner of the region on Sunday. This slide probably occurred 1-2 days earlier. It released on a northeast aspect in the alpine. There were a handful of large persistent slab avalanches triggered on basal facets in the mountains north of Kispiox last week.

Snowpack Summary

Roughly 15-30 cm of snow has fallen in the past week, with the highest accumulations occurring in the southwest of the region. Strong to extreme ridgetop winds have shifted the new snow into hard or soft wind slabs in exposed terrain, adding to an ongoing wind slab problem. A layer of surface hoar from early January can be found in isolated locations between 60 and 140 cm 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. In shallower areas the snowpack 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

Ongoing snowfall and strong winds continue to create fresh wind slabs at treeline and in the alpine. Watch for triggering in the lee of ridge crests and terrain breaks.

Be cautious as you transition into wind affected terrain.>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 the potential for full depth avalanches due to deeply buried weak layers.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 9th, 2016 2:00PM