Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Banff Yoho Kootenay.
Potential for large avalanches persist. Conservative route choices remain the theme of the day. Iceclimbers should pay attention to freezing levels and adjust there route choices accordingly.
Weather Forecast
Friday will be mainly cloudy with some isolated flurries. Freezing levels will be around 1300m and the winds will be moderate from the west. There will be a continued cooling trend for Saturday.
Snowpack Summary
10-20 cm of fresh snow (at treeline) and up to 50 cm of storm snow in the past week have formed a cohesive slab overtop of a series of weak layers. Test results show sudden shear failures on these layers. Moderate SW winds have created fresh wind slabs on lee aspects at treeline and above. Below 1800 m the snowpack is moist from rain event on Thur.
Avalanche Summary
A series of loose wet avalanches triggered by warm weather and rain were observed at lower elevations on Thursday. Skihills reported several smaller windslab avalanches near ridgetops. A Skier triggered a size 2.5 avalanche on Lipalian 2 (west aspect) outside Lake Louise ski area occurred on Wednesday.
Confidence
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.
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.
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.