Regions
Kootenay Boundary.
Avalanche conditions could vary dramatically between aspects and elevations Decision making may be more tricky than the Moderate danger rating implies. There is a chance that the forecast rain could wake up a layer of buried surface hoar at treeline.
Confidence
Low - Freezing levels are uncertain on Friday
Weather Forecast
FRIDAY: rain or wet snow, up to 15cm overnight and through the day, light southerly winds, freezing level of 2000m. SATURDAY: another 5-10cm of snow overnight, becoming scattered flurries through the day, light westerly winds, freezing level of 1500m. SUNDAY up to 15cm new snow, light westerly winds, freezing level of 1700m.
Avalanche Summary
Loose wet avalanche activity up to size 2 has been associated with the warm temperatures and strong solar radiation.
Snowpack Summary
Wet or moist snow can be found on solar aspects capped by a melt freeze crust that may break down through the day. Pockets of dry snow can still be found on high north facing slope where increasingly hard to trigger wind slabs can be found at ridge line. An older burred crust can be found down 40cm that extends well up into the alpine. Below this, a thick slab rests on a layer of surface hoar that was buried earlier in January and is now down 80-130 cm. This layer continues to pose a low probability high consequence threat, producing sudden planar fractures in snowpack tests under moderate to heavy loads. I'm going to keep it on my radar until the snowpack cools off again. A rain crust from early December sits near the base of the snowpack.
Problems
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.