Summary
Confidence
Fair - Intensity of incoming weather is uncertainfor the entire period
Weather Forecast
Sunday: 5cm of snow - Freezing level at 500m - moderate westerly windsMonday: 20-30cm of snow - Freezing level at 400m - strong southwest windsTuesday: light to moderate snowfall - Freezing level at or around surface - light southwest winds
Avalanche Summary
On the 23rd a natural avalanche cycle took place in the northern part of the region producing slides up to size 3. In the south, observations were extremely limited due to poor visibility. Expect widespread natural avalanche activity throughout the forecast period with expected snow and wind.
Snowpack Summary
Over the past week the forecast region got slammed by snow, strong to extreme wind and fluctuating freezing levels. Including the 18cm that fell on friday night, the southern part of the region has received about 120cm of new snow (Kasiks, Terrace areas). Locations to the north are seeing less (Stewart up to 75cms). Alpine observations have been limited and wind sensors have been disabled by rime, but I suspect new snow has been blown around by strong southwest winds creating wind slabs on lee slopes.In addition to the more obvious direct-action storm instabilities that are expected with the forecast weather, local avalanche professionals have some other concerns: Surface hoar that formed during the winter solstice sits approximately 35cm below the surface and will become more reactive with more wind and snow. As well, the crust-facet combo (extends up to alpine elevations in the south and to 1000m in the north) from the early december dry-spell sits about 150cm below the surface and has not gone away. Any avalanches on this layer would be highly destructive and are probably waiting for the right load or trigger. The mid and lower snowpack are settled out and strong. Snowpack depths in the Kasiks, Terrace areas have reached the 300cm mark. Further north Smithers, Bear Pass depths are ranging from 190-260cms.
jlammers,
Avalanche Canada
