Weather Forecast
Thursday: A mix of sun and cloud, with a few afternoon flurries. High near -17.Friday: Cloudy with morning sunny breaks, 70% chance of afternoon flurries. High near -12. Snow and trending milder Friday night, light to moderate accumulation. Saturday: Periods of snow, moderate accumulation. High near -5.
Avalanche Summary
A widespread natural avalanche cycle occurred in the Elk Valley on Tuesday/ Tuesday night, with numerous slabs up to size 3 releasing in the alpine on mainly east-facing slopes. Initial reports suggest that these released up to 2m deep on wind-loaded slopes. South of the Crowsnest, a few size 1-2 slabs were reported.
Snowpack Summary
Storm snow totals average around 40cm, with local variability. Cold temperatures have limited storm slab development, however numerous slabs did release during peak loading during the storm. In many areas, fast-moving sluffs remain a key concern. Besides new storm/wind-related concerns, the main layer we're watching in the region is a surface hoar layer buried in early December. It's down about 1m in the Flathead and recently exhibited hard, sudden planar/full propagation results, meaning that it was stubborn to trigger but could create a large avalanche. Facets sandwiched between two firm layers in the top metre of the snowpack are being monitored in the south-east.
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.
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.