A large natural avalanche cycle is occurring. Avoid all avalanche terrain.
Weather Forecast
The storm is coming to an end, and Tuesday will bring cloudy skies with sunny periods. Temperatures will remain cool with the temperature reaching a high of -19 °C. Wednesday should be a bit milder with more sun, and then a warm, windy and snowy day is expected on Thursday.
Avalanche Summary
Visibility was very limited today, but some natural avalanche activity was observed today in Alpine and Treeline terrain. One of the observed avalanches stepped down to the November persistent weak layer. We strongly suspect that a widespread avalanche cycle is occurring on all aspects and at all elevations.
Snowpack Summary
15 to 20cm of new snow in the past 24hrs brings storm snow totals to near 100cm at Treeline over the past 3 days. This storm snow sits on a previously formed dense wind slab in many parts of the forecast area. Widespread wind effect in Alpine and open areas at Treeline. Suspect significant wind slab development. Forecasters have a concern that the new load will cause failures in the deeply buried weak layers of Dec 18 and Nov 12, causing deep and destructive avalanches.
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.
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.
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.