Regions
Kootenay Boundary.
Avalanche danger is high due to loading from new snow or rain, and wind.
Confidence
Fair - Intensity of incoming weather systems is uncertain
Weather Forecast
The Pineapple Express which has been bringing lots of moisture and warm temperatures over the Southern part of BC, will continue to spread heavy precipitation until the end of the day Saturday, taper off on Sunday and pick up again on Monday as another storm passes through. Freezing levels are expected to hover between 1700m and 2000m and winds to blow moderate to strong from the southwest on Saturday.
Avalanche Summary
A natural slab and loose avalanche cycle up to size 2.5 within the new snow started on Thursday afternoon. I suspect that avalanche conditions were similar on Friday even though poor visibility did not allow for good observations.
Snowpack Summary
The top 30 to 40 cm of snow sitting over the late January crust is now either wet or moist above ~1900m. The rain forecast up to 1900m through Saturday will continue to break down the late January crust, increasing the possibility of avalanches stepping down to deeper weak layers. Avalanche danger will therefore stay high and traveling in the backcountry will remain very dangerous. The mid-January weak layer of buried surface hoar is now down 35-75 cm. The mid-December crust/facet/surface hoar combo is found down 60 - 110 cm and could come out of its dormant stage making for some very large avalanches.
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.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.
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.