Regions
Northwest Inland.
Light snowfall with strong to extreme southwest winds are expected to form new wind slabs on Sunday. Use extra caution in wind-affected terrain and watch for signs of wind loading.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
A storm system is expected to reach the region Sunday morning. 5-10cm of new snow is expected by Sunday night. Alpine winds are expected to be strong to extreme from the southwest and freezing levels are forecast to reach around 800m in the south of the region. The stormy conditions should ease on Monday but light snowfall may continue during the day. Alpine winds should progressively ease to become moderate from south. Freezing levels are expected to hover around 800m in the south of the region. Another weak storm system is currently being forecast for Tuesday.
Avalanche Summary
No new avalanches were reported on Friday. On Thursday, a couple of size 2 wind slab avalanches were reported from steep northwest aspects in the alpine. These occurred in the upper Kispiox area and were typically 40cm deep slabs. In the north of the region on the border of the Northwest Coastal region we had a report of remotely triggered avalanches up to size 1.5 in the alpine and at treeline.
Snowpack Summary
The region has a mix of wind slabs and developing storm slabs. In higher snowpack areas in the northwest of the region, the storm slab has become reactive to human triggers. In most other areas the wind slabs are thin and stiff. Buried surface hoar is layered through the thin snowpack, and cool temperatures as well as limited loading have preserved these weak layers. The mid pack that was reported to be well settled may have now facetted in the shallower areas, and the deeper basal layers are almost certainly facetted and weak. We have not heard of any full depth releases on weak basal layers yet.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.