Continued wind, snow and warming will add more stress to buried weak crystals. Very large avalanches have been running from the alpine to valley bottom. Conservative terrain selection remains critical.
Summary
Confidence
Fair - Due to the number of field observations
Weather Forecast
An active moisture stream will continue to bring moderate snowfall with locally heavy accumulations in the south of the region. Monday night: Up to 25cm of new snow / Extreme southwest winds / Freezing level at 1200m Tuesday: Moderate snowfall in the morning easing by mid-day / Strong southwest winds / Freezing levels at 800m Wednesday: Light snowfall with up to 10cm falling that evening / Strong southwest winds / Freezing level at 800m Thursday: About 10cm of new snow / Extreme southwest winds / Freezing level at 1200m
Avalanche Summary
A few close calls on Sunday suggest that the region has undergone a fairly active avalanche pattern. In the Hankin area, a skier accidentally triggered a size 2 avalanche which resulted in a partial burial and minor injuries. The avalanche was reported to have occurred on a wind-loaded, northeast-facing slope at treeline, and may have stepped-down to deeper layers. In the Sinclair area, a snowmobile may have been the trigger for a size 3 avalanche. The avalanche had a crown between 1 and 2 metres, and propagated up to 200 metres wide. It failed on a wind-loaded, north-facing alpine slope and may have failed on the November crust facet combo. With more stormy weather on the way, I'd expect ongoing storm slab activity with the potential to involve deeper, more destructive layers.
Snowpack Summary
Continued snowfall has contributed to ongoing storm slab development. Warm temperatures have promoted rapid slab settlement, while rain has created wet loose surface snow at lower elevations. Southwest winds continue to build slabs on leeward slopes with cornices overhead in exposed treeline and alpine terrain. A crust/ surface hoar combo buried in the middle of January may be around 50-80 cm deep now. In the mid-pack, a crust weakness buried in mid-December seems to be unreactive for the time being. Near the base of the snowpack is the crust-facet combination buried in November that seems to have "woken-up" in some terrain in response to warming and heavy loading from wind and snow.
jlammers,
Avalanche Canada
