There is a lot of uncertainty surrounding the intensity of precipitation amounts in the region. Rising temperatures combined with new snow and wind are pushing the avalanche danger to HIGH.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Strong southwest winds and 10-15 cm of new snow expected overnight with freezing levels dropping to about 1000 metres by morning. Overcast with moderate southwest winds and 5-10 cm of new snow during the day on Thursday as the freezing levels rise to about 1300 metres. Clearing and cooler with light winds on Friday and freezing levels at valley bottom by morning. Mostly clear on Saturday with light winds and temperatures near -10 in the alpine.
Avalanche Summary
Explosive control released storm slabs up to size 2.0 in the alpine that were 10-20 cm deep on Wednesday. Natural avalanches were heard during the day on Wednesday but poor visibility limited observations. Natural wind slabs and natural cornice falls were reported up to size 1.5 on Tuesday. Several natural and human triggered size 1 wind slabs were reported on Monday.
Snowpack Summary
10 cm overnight combined with another 10 cm during the day on Wednesday has developed storm slabs at higher elevations. Recent winds have caused widespread wind affect in exposed alpine and tree line terrain forming touchy wind slabs on lee features. These are now buried by a blanket of new snow. Last week's 20 cm of low density snow buried a variety of old surfaces (wind scoured, old wind slabs, surface hoar up to 20 mm in sheltered terrain, and/or faceted old snow). Deeper in the snowpack, the mid-December persistent weak layer of facets has been more prominent and reactive in the Corbin area than areas closer to Fernie. The layer is generally considered dormant at the moment in deeper snowpack areas, but its status may change as the temperatures warm throughout the week.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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 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.