Confidence
Fair - Freezing levels are uncertain on Thursday
Weather Forecast
A frontal system over Northern BC tracks inland tonight/tomorrow, the Northern parts of the region may see light amounts of precipitation Wednesday into Thursday am. Wednesday: Cloudy, with scattered flurries. Ridgetop winds moderate-strong from the NW. Treeline temperatures near -10. Freezing levels valley bottom rising to 8-1300 m by late afternoon. Thursday/Friday: Few flurries in the am. Mix of sun and cloud in the afternoon. Overcast on Friday. Ridgetop winds moderate from the West, getting stronger from the SW through to Friday night. Flurries expected overnight. Freezing levels 12-1200 m both days.
Avalanche Summary
A widespread natural cycle occurred on Monday. Operators have reported naturals from size 1-3, on all aspects and elevations. Numerous skier triggered avalanches also occurred all size 1. I suspect conditions will still remain touchy, and unpredictable.
Snowpack Summary
Over the weekend, 60-100 cm snow has fallen. Strong winds and fluctuating temperatures are creating storm slabs and wind slabs on a widespread basis. Persistent weak layers (surface hoar, facets, crusts) buried in February are the main concern at all elevations and could be easily triggered by storm slabs, wind slabs or sluffs, or with a light additional load (like a sled or skier). Avalanches may be unexpectedly large, given the amount of fresh snow. If the sunshine appears, I'd be weary of south facing slopes affected by solar radiation. Large cornices have formed, and may act as potential triggers on slopes below. They may step down to a persistent weak layer.
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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.