A gradual cooling trend with forecast precipitation, should bring snow to the alpine and then slowly to lower elevations.
Summary
Confidence
Moderate - Freezing levels are uncertain
Weather Forecast
Freezing levels should slowly drop overnight down to about 1000 metres. Expect 5-10 cm of snow in the alpine by Thursday morning with moderate southwest winds. Broken skies or scattered cloud during the day on Thursday with freezing levels rising sharply back to about 1800 metres. Another pulse of moisture should bring 10-15 mm of rain to lower elevations by Friday morning, and snow above about 1500 metres combined with moderate southerly winds. Continued unsettled conditions during the day Friday with another 10-15 mm of rain in the valleys and snow at higher elevations as the freezing level slowly drops down to about 1000 metres. On Saturday the freezing level should remain below 1200 metres with light southwest winds, and light precipitation.
Avalanche Summary
No new observations. On Monday, warming and solar radiation triggered widespread loose wet avalanche activity in steeper, sun-exposed terrain. Large cornice collapses were also observed. Of note, warming also triggered a size 3.5 slab avalanche on the south face of Mt Currie. Similar action likely occurred on Tuesday. The gradual cooling trend will strengthen the upper snowpack making avalanches triggered by warming less likely.
Snowpack Summary
Variable new crusts have formed in the alpine and at treeline. Supportive crusts on solar aspects resulted in corn skiing in some areas. Breakable crusts were reported from Northerly aspects on Tuesday. Cornices are also reported to be huge and collapse has become more likely with daytime warming. About 50-90cm below the surface, you'll likely find a rain crust which formed on January 28th. This crust is widespread and exists up to about 2050m. Where it still exists, the mid-January surface hoar layer may be found between 130 and 200 cm below the surface. The combination warm temperatures and subsequent gradual cooling is making avalanches failing on these deeper layers unlikely.
triley,
Avalanche Canada
