The current snowpack structure is atypical for this region, especially at this time of year. Check out this blog post for more details: http://www.avalanche.ca/blogs/VQxmdCUAAJZDmnXn/rainsnowwind
Confidence
Fair - Due to the number of field observations
Weather Forecast
The region will see generally light precipitation on Saturday morning. A weak ridge will develop on Sunday before another system arrives on Monday. Saturday: About 5cm of snow / Moderate southwest winds / Freezing level at 1500m Sunday: Mix of sun and cloud / Moderate to strong south winds / Freezing level at 1600m Monday: 5-10cm of snow / Light southwest winds / Freezing level at 1700m
Avalanche Summary
Over the past week, isolated slab avalanches to size 2 have occurred on persistent weaknesses buried on March 11th. In a few cases, avalanches failed with light inputs such as remote triggers. New snow and wind will create its own mix of reactive surface instabilities, but it will also add load to these deeper, more destructive layers. There's a fair bit of uncertainty as to how the March 11th interface will react to storm loading. That said, I'd resist heading into aggressive higher elevation as any releases on this layer would likely be destructive in nature.
Snowpack Summary
By Saturday morning I'd expect new storm slabs to have formed in response to steady wind, snowfall and warm temperatures prior to the weekend. Cornices may also be fragile. A crust/facet persistent weak layer, buried up to 60 cm down, has started to play up in isolated terrain (see avalanche summary). Avalanche problems associated with this layer may linger for a while with the potential for surprisingly large and destructive avalanches. Below this, the snowpack is reported to be generally well-settled and strong. At lower elevations, the diminishing snowpack is trending isothermal (same temperature throughout).
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.