Solar radiation is quite strong whenever there is a break in the clouds. Evaluate sunny slopes carefully after midday.
Weather Forecast
Warm overnight temperatures and high freezing levels are forecast for the next 2 days. Before noon on Saturday, heavy snowfall will begin in the Icefields area with accumulations up to 25cm. This new precipitation will arrive with strong, gusty winds, and cooler temperatures. Warming and clearing should follow the storm on Sunday.
Snowpack Summary
The primary concerns for the snowpack are: 1. Isothermal conditions, especially on solar aspects, 2. Deep persistent weaknesses at the base of the snowpack, and 3. Windslabs in lee Alpine and treeline features. The well settled upper snowpack layers, especially at higher elevations, are bridging lower weaknesses for now.
Avalanche Summary
New avalanche activity is small & restricted to steep solar slopes usually near rocky terrain. Additional inputs of energy from rain, strong solar radiation, & poor refreezing temperatures overnight will exacerbate this problem. Windslabs could be triggered by skiers, and these smaller avalanches could trigger the basal weakness.
Confidence
Intensity of incoming weather systems is uncertain on Saturday
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.
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.