Snow, wind, and rising freezing levels will increase the avalanche danger. Deeply buried persistent weak layers may be triggered by the increased load from the storm. Patience and a conservative approach to terrain are recommended.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
5-10 cm overnight with extreme southwest winds and freezing levels at or just above valley bottoms. Another 5-10 cm during the day on Friday with strong southwest winds and freezing levels spiking up to about 1000 metres. Light snow combined with moderate southerly winds and dropping freezing levels on Saturday. On Sunday, continued light snow with increasing southerly winds and rising freezing levels.
Avalanche Summary
On Wednesday there was a report of an accidentally triggered size 1.0 avalanche on a short steep roll below treeline at 1500 metres in the Ashman area. The crown was 30-50 cm deep and 25 metres wide; compression tests on this layer produced easy-moderate sudden shears. Some loose dry avalanches up to size 1.0 were reported from the Hankin area on Tuesday in the alpine on steep east aspects.
Snowpack Summary
5-10 cm of new snow may be sitting on a layer of surface hoar that was buried in the last few days. Moderate southeast winds have developed new wind slabs in the alpine and at treeline, and forecast snow and southwest winds are expected to build new storm slabs on all aspects. Below 1200-1400 m the new snow probably sits on a crust. Fresh soft wind slabs are likely in exposed lee terrain. The early or mid January surface hoar layer is reported throughout the region and is generally 30-50 cm deep. Observers have found this persistent weakness on all aspects and at all elevations. It consistently produces moderate "pops" results in snowpack tests. Below this, the Boxing Day surface hoar problem may also be lurking. The mid and lower snowpack is generally quite weak and faceted, especially in lower snowpack areas.
triley,
Avalanche Canada
