Lingering storm instabilities will persist for several days, especially in the alpine. Human-triggering remains likely and conservative decision-making remains critical.
Summary
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
A ridge of high pressure will build over the interior on Tuesday. Mostly cloudy conditions are expected but sunny breaks are possible in the afternoon. Light scattered flurries are possible in the morning but things should dry out by the afternoon. Alpine winds should remain light. Freezing levels on Tuesday are expected to be around 1600m but should fall to near valley bottom Tuesday overnight. On Wednesday, mainly dry conditions are expected with a mix of sun and cloud. Freezing levels are forecast to climb as high as 2000m by the end of Wednesday. Thursday might be the first day with a lot of sun and freezing levels are forecast to climb to around 2500m.
Avalanche Summary
Widespread natural, human-triggered, and explosive controlled avalanches up to size 3 were reported on Friday through Sunday. This includes both storm slabs and persistent slabs. Many avalanches started dry and ended wet, running to valley bottom. On Sunday, a skier was involved in an accident in the Canyon Creek area. The subject was caught in a size 2.5 persistent slab which resulted in serious injuries. The avalanche released on the mid-January surface hoar layer down around 80cm. On Tuesday, natural avalanches remain possible at upper elevations but are generally not expected. Human-triggering remains likely and travel in avalanche terrain is not recommended until the storm slab has had a chance to stabilize.
Snowpack Summary
40-60cm of rapidly settling storm snow sits over the late-Jan weak layer at higher elevations. Rain has soaked the snow surface up to around 2000m and moist snow is reported to at least 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 50-80cm and has been very reactive in some areas. The mid-December weak layer is down around 1m but its reactivity has been isolated recently. The mid-November weak layer of crusts and facets can still be found near the bottom of the snowpack. It has been unreactive lately, but should remain on your radar, especially in shallow snowpack areas.
rbuhler,
Avalanche Canada
