Confidence
Fair - Freezing levels are uncertain
Weather Forecast
Sunday: Mix of sun and cloud with an area of warm air moving into alpine elevations. Above freezing temperatures are expected in the Alpine.Monday: Continued warm air at higher elevations with light to moderate Southwest winds and no precipitation.Tuesday: Cloudy with light to moderate Southwest winds and seasonal temperatures in the alpine.
Avalanche Summary
Natural loose snow and storm snow avalanches size 1.0-1.5 were reported from steep South aspects in the alpine and at treeline in the Duffey Lake area. Natural avalanches size 1.0-1.5 from steep wind loaded pockets at ridgeline were reported from the Coquihalla, as well as several size 2.0-2.5 storm slab avalanches from the steep North aspect of Mount Cheam.
Snowpack Summary
New snow is expected to be poorly bonded, especially on wind-loaded slopes. Snowpack depths vary greatly across the region with 180cm at treeline in the Cascades but only about 80cm in the Duffey Lake area, and terrain below treeline is still mostly below threshold for avalanche activity. In general the snowpack is shallow with a faceted and weak lower half, but also highly variable. Snowpack testing on a NW facing slope at 2150m in the Duffey Lake area on Thursday produced easy sudden planar compression test results, and a RB2, whole block release Rutschblock result down 27cm on the late-December surface hoar, this layer now has an additional 15-25 cms since the Thursday evening storm. Early season riding hazards such as rocks, stumps and logs are lurking below the surface at treeline elevations and below.
Problems
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.
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.