Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
The pattern turns cooler, with some sunny skies. The next low pressure system will begin to effect the region on Tuesday, bringing cloud cover and new snow.Monday: The ridge will move over all regions and dominate the weather pattern. Lingering cloud until mid-day with possible sunny skies in the afternoon. Ridgetop winds light from the South. Alpine temperatures near -7 and freezing levels around 1200 m in the afternoon. Tuesday: The low will bring a milder southerly flow over the region and push a weak and poorly timed upper wave across the Kootenay, Columbias and South Rockies. Alpine temperatures -7 and freezing levels 1400 m. Ridgetop winds moderate from the SW. Wednesday: Moderate snow amounts with ridgetop winds light from the SW. Alpine temperatures near -6 and freezing levels 1600 m falling to valley bottom overnight.
Avalanche Summary
On Saturday a widespread natural avalanche cycle occurred. Most of the avalanches were size 1.5-2 with a few isolated size 2.5. Natural cornice fall occurred triggering slabs on the slopes below. At lower elevations loose wet avalanche activity occurred up to size 1.5.
Snowpack Summary
Up to 40 cm of storm snow has fallen. Storm slabs have been reactive naturally, especially on slopes lee to the wind. The new snow has been transported onto lee slopes by strong west and southwest winds creating wind slabs. Cornices have grown large on ridgelines and may become weak, especially if the sun shines through. In areas unaffected by the wind, loose dry sluffs are likely.Mid and lower snowpack layers are generally well settled.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.