Another day of strong sun and warm temperatures will maintain very dangerous avalanche conditions on Wednesday. Travel in avalanche terrain is not recommended.
Weather Forecast
Tuesday night: Clear. Light southwest winds. Freezing levels remaining near 3300 metres.Wednesday: Sunny. Light variable winds. Alpine high temperatures around +8 with freezing levels still at 3300 metres, dropping slightly overnight.Thursday: Sunny. Light east winds. Alpine high temperatures around +7 with freezing levels around 3100 metres, remaining elevated overnight.Friday: Sunny. Light variable winds. Alpine high temperatures around +6 with freezing levels around 3000 metres, dropping overnight to 2200 metres by mid-morning Saturday.
Avalanche Summary
Reports from Sunday and Monday showed a continuation of natural loose wet avalanche activity focused on sun exposed aspects, with some releases reaching size 2.5 as they gouged into the snowpack to entrain more mass. Several large persistent slab releases have also been noted failing on large alpine features and reaching size 2.5. Failure planes in these events remain uncertain, but at least one northeast aspect figured in these reports, showing some increasing potential for shaded aspects.Saturday's reports were of significant warming but only small loose wet avalanches. Neighbouring regions (for example Kananaskis Country) where the snowpack is thinner and weaker entered a natural avalanche cycle involving most aspects, most elevations, and most snowpack layers.Looking forward, the type of activity shown above can be expected to continue, expand to all aspects, and perhaps intensify as temperatures remain elevated and overnight cooling remains weak.
Snowpack Summary
Upper snowpack: Getting warm and moist during the day, maybe forming weak crusts overnight that deteriorate during the day. On sunny aspects there may be buried crusts serving as sliding layers. On lee slopes there may be buried hard layers of wind effected snow (buried wind slabs).Mid pack: The mid-snowpack consists of sugary faceted grains (facets) of different hardness. Two older layers of surface hoar still exist down 55-80 and down 95-150 around 1600-1900m. As warmth penetrates into the snowpack each day, it progressively increases strain on these layers.The lower snowpack has recently been reported to be strong in deep snowpack regions, but its strength is in doubt in shallower areas where the long February cold was able to penetrate and weaken even basal snowpack layers. Forecasting how many sunny days and warm nights it's going to take to wake up deeper layers is tough, but we can say with confidence that it's a good time to stand aside and let the mountains shed their coat. Stability will improve greatly when temperatures cool off.
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.
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.