Storm problems will persist on Sunday, especially at higher elevations. If the sun breaks through, solar triggered avalanches are expected. Conservative decision making remains critical and travel in avalanche terrain is not recommended.
Summary
Confidence
Fair - Due to the number of field observations
Weather Forecast
Another pulse of moderate-to-heavy precipitation is expected Saturday overnight with freezing levels remaining at around 1800m. Precipitation should ease during the day on Sunday but light scattered showers are expected to persist, at least in the morning. Broken or scattered sky cover is possible in the afternoon and some areas may see sun. Freezing levels should remain between 1600 and 1800m. Alpine winds are forecast to be moderate from the SW on Sunday morning and ease during the day. The next storm pulse is expected to arrive Sunday overnight and persist through the day on Monday. Freezing levels may drop Sunday overnight but this depends on the amount of clearing between the storm pulses. Freezing levels on Monday should be around 1500m and alpine winds are expected to be moderate from the SW. The end of the storms is forecast for early Tuesday. Lingering flurries and sunny breaks are both possible on Tuesday. Unfortunately, the warm air is expected to persist for several days following the end of the storm and freezing levels will remain unseasonably high.
Avalanche Summary
Widespread natural, human-triggered, and explosive controlled avalanches up to size 3.5 were reported on Friday and Saturday. On Sunday, natural avalanches remain likely at upper elevations where storm and wind loading continue. At lower elevations which have seen rain, natural activity is less likely but remains possible. Human-triggering remains very likely at higher elevations on Sunday. If the sun comes out on Sunday, solar aspects will likely see natural avalanche activity.
Snowpack Summary
Up to 80cm of recent storm snow has fallen over the late-Jan weak layer. Rising freezing levels during the storm have created upside-down snow conditions and highly reactive storm slabs. Rain has soaked the snow surface up to around 2200m. Strong SW winds have formed wind slabs in exposed leeward terrain features. The storm slab sits on an old rain crust at lower elevations, variable surface hoar, and/or wind affected surfaces at higher elevations. The mid-January surface hoar is typically down over 80-120cm and is still reactive in some areas. The mid-December weak layer is down 100 to 150cm. It has generally been unreactive but may wake-up with the new storm loading.
rbuhler,
Avalanche Canada
