Regions
Kootenay Boundary.
Avalanche danger can rise quickly with afternoon warming and solar radiation. Be aware of changing conditions and overhead hazards.For more insight into spring danger ratings, check out this blog post.
Confidence
Poor - Due to the number of field observations
Weather Forecast
Wednesday: Cloudy with sunny breaks and scattered flurries (~5 cm). The freezing level is around 1500 m and ridge winds are moderate from the SW. Thursday: Mainly cloudy with showers or flurries 5-10 cm. The freezing level is around 1800 m and winds are light but gusty from the south. Friday: Mainly cloudy with showers or flurries. The freezing level is around 1800-2000 m and ridge winds are light from the S-SW.
Avalanche Summary
Expect loose wet avalanches in steep terrain if it is raining or during sunny periods, especially if the sun or rain is affecting fresh snow. New storm of wind slabs may develop in higher terrain if we see significant new snow accumulation. Make conservative terrain choices if you see 30 cm of new snow or more in 24-48 hours or significant loading from strong winds. There is still potential for deep persistent slabs to wake up. This is most likely during periods of heavy rain or warm temperatures and strong solar radiation. Your best bet is to pack it in when the snow surface is becoming really wet and mushy.
Snowpack Summary
This is a broad general summary of conditions in the region. This summary is based on very limited field data and should be supplemented with local observations to help assess avalanche danger. Over the past week or so we have seen moderate amounts of moist new snow mixed with showers or periods of rain below 1600-1800 m. Westerly winds have likely formed pockets of wind slab at higher elevations in lee of ridges and terrain features. The upper snowpack generally consists of layers of moist or wet snow mixed with several well bonded crusts. Most areas are likely below threshold for avalanches below 1300-1500 m depending on aspect. The late January/early February persistent weak layer is deeply buried but could still wake up during periods of heavy precipitation (especially rain) or significant warming and solar radiation. Be particularly wary of this on large open alpine slopes. Cornices are large in some areas and should be given a wide berth.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.