Conditions are tricky with a complex mix of avalanche problems and weather factors. Err on the side of caution when dealing with such uncertainty.
Confidence
Moderate - Freezing levels are uncertain
Weather Forecast
SATURDAY NIGHT: Passing frontal system will bring 5-10 cm of new snow with strong southwest winds.SUNDAY: Light flurries easing off throughout the day, moderate southwest winds, alpine temperatures around -4 CMONDAY: Chinook conditions, cloudy with sunny breaks with possible flurries in the southeast part of the region, strong west winds, freezing level around 1900 m.TUESDAY: Cloudy with sunny periods, moderate southwest winds, freezing level around 2100 m.
Avalanche Summary
On Saturday, several loose wet avalanches were reported from steep solar aspects and a size 2 wind slab was reported on a windloaded ridge crest. On Thursday, explosive avalanche control along the White River (in the northwest corner of the region) produced over 10 deep persistent slab avalanches releasing on basal facets. Most of the avalanches were size 3, included several than ran full path to valley bottom taking out mature forest and blocking the river with up to 8 m of debris. An older size 2 natural avalanche failing on basal facets was also reported in the Crossing Creek area.New snow will form fresh storm slabs on Sunday, while warming and loading may stress deeper weaknesses and create the potential for large destructive avalanches.
Snowpack Summary
Warm temperatures from an alpine inversion have rapidly settled the most recent 20-30 cm of storm snow. March has delivered regular storms with roughly 50-90 cm of snow sitting above crust and facet interfaces from February. In some areas the snow above these interfaces may have a poor bond. The mid-pack in this region is generally strong, but the bottom third of the snowpack is composed of weak sugary facets roughly 1-1.5 metres deep. This remains a concern and should be on your radar, especially with the recent loading and upcoming warming.
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.
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.