Regions
Northwest Inland.
Forecast snowfall amounts for Tuesday night are highly variable throughout the region. In areas that receive more than 20cm of new snow, the avalanche danger may be HIGH.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Tuesday night and Wednesday: Between 8-20cm of new snow in the overnight period with an additional 5-10 cm during the day The highest accumulations are expected in the southwest corner of the region closer to Telkwa Pass / Extreme southwest winds / Freezing level at 650mThursday: Light flurries / Light and variable winds / Freezing level at surfaceFriday: Light flurries / Light and variable winds / Freezing level at surface
Avalanche Summary
No recent avalanches have been reported from this region, although there was likely a round of fresh wind slab activity in response to new snow and wind on Sunday night. More snow and wind on Tuesday night will promote ongoing wind slab activity.Despite possible breaks in the weather, wind slabs will likely remain sensitive to human triggering due to underlying persistent weak layers.
Snowpack Summary
Between 3 and 15 cm of new snow fell on Sunday night. Extreme winds have redistributed the new snow into fresh wind slabs in exposed terrain. More wind and snow on Tuesday night will add to this developing wind slab problem. The recent storm snow sits over a highly variable interface resulting from over a week of clear skies, cold temperatures, and strong outflow winds. This mid-December interface consists of scoured surfaces and hard wind slabs in wind exposed terrain, widespread faceting of the upper snowpack, and surface hoar in sheltered areas. The new snow may bond poorly to this interface.Snowpack observations have been very limited recently in the region. The snowpack is very shallow throughout the region and widespread faceting of the entire snowpack is expected in most areas. A thick rain crust that formed in early November is probably near the bottom of the snowpack and is expected to be developing facets. Reports from the Ningunsaw Pass area and the far north of the region suggest that depth hoar is developing in shallow snowpack areas.
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.