Summary
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
Wednesday: A Pacific frontal system starts to affect the interior regions. Cloudy with light snowfall, moderate to strong west winds. Freezing level in the valley bottom.Thursday: Light snowfall, alpine temperatures -7, moderate west winds.Friday: Light snowfall, alpine temperatures -5, freezing level 1100m, winds moderate west and southwest.
Avalanche Summary
Recent avalanche activity from the past 3 days seems to be isolated to a few windslab releases up to size 2.5. These were running within the storm snow in the alpine and at treeline elevations from a variety of aspects. Reports continue to roll in about the extent of the avalanche cycle running to size 3+ from last Thursday and Friday. This is a reminder that the October facet/crust layer near the base of the snowpack could still be reactive. Although unlikely, given enough load and/or hitting the sweet spot i.e. thin area, it may be possible to trigger this layer resulting in a large and destructive avalanche.
Snowpack Summary
Up to 50cm of recent new snow has been redistributed by moderate to strong winds from a variety of aspects creating new wind slabs at the tree line elevation and above. This snow lies on top of old wind slabs, a buried rain crust that exists below 1600m and a surface hoar or facet layer that is down 100-150cm deep. Snowpack depths vary, but in general 175 cm of snow can be found at treeline, with 125-300 cm in the alpine. In some places we're still dealing with a relatively thin snowpack (thanks to a windy early season). The basal facet/crust combo (weak sugary snow above and below a crust) near the ground was active in an avalanche cycle last Thursday and Friday. This weakness may be difficult to trigger but if triggered, will result in very large, destructive avalanches.
mbender,
Avalanche Canada
