Confidence
Fair - Freezing levels are uncertain on Monday
Weather Forecast
Monday: Mix of sun and cloud. Light to moderate west winds. Freezing level 2400m.Tuesday: Cloudy with scattered flurries. Light westerly winds. Freezing level 1500m.Wednesday: Mainly cloudy with some sunny breaks. Light west winds. Freezing level 1800m.
Avalanche Summary
Recent reports from the past 3 days indicate natural avalanches running to size 3 from southerly aspects in the alpine and at tree-line.
Snowpack Summary
Mainly sunny weather and the freezing level reaching up to 2300m has created moist snow and/or a crust on all aspects and elevations except for high elevation north-facing terrain. This has helped to settle out last week's storm snow accumulations. Moderate west and northwest winds have redistributed what little dry snow still exists at upper elevations into wind slabs immediately lee of ridge crest.Three persistent weak layers exist in the highly variable snowpack of the South Columbia region:The mid-March sun crust/surface hoar layer down 50-80cm seams to have gone dormant for the time being.The early-March crust/facet/surface hoar layer down around 80-120cm has become less susceptible to human triggering, but still has the capacity to produce large avalanches.The mid-February crust/facet/surface hoar combo is typically down 150 - 200cm. Direct triggering of this layer has become unlikely, however, cornice fall, a smaller avalanche in motion or prolonged warming could wake this layer up, which would result in very large and destructive avalanches.
Problems
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.