Regions
Banff Yoho Kootenay.
Cool temperatures and up to 45cm of new snow have brought a brief return to winter conditions. Use caution in steep terrain and be aware that the new snow may hide a very weak, rain saturated base especially in thin areas.
Weather Forecast
Continued cool temps overnight with lows of -7'C and an additional 5cm of snow and light winds. Sunday we expect another 10cm of snow with alpine temperatures between -4'C and -1'C and light winds. Monday and Tuesday are a mix of sun and cloud, continued cool alpine temperatures and a trace of new snow. Freezing levels remain near the 2000m level.
Snowpack Summary
Soft slabs forming at tree line with light winds. 30-45cm of new snow overnight at tree line is generally bonding well to the moist snow beneath it. Moderate shears were present in the moist snow layer. The basal facets remain a concern, especially in thin areas where the lower snowpack is completely saturated with the recent rainfall.
Avalanche Summary
Sluffing out of steep terrain up to size 1 today. Local ski patrollers were able to ski cut small wind loaded pockets up to size 1.5. Two size 2 skier accidental avalanches occurred in thin areas near the Lake Louise ski area today with failures to ground in moist facets. Minimal natural activity was observed however visibility was limited.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
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.
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.