Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain

Tuesday night: Cloudy with flurries bringing 5-10 cm of new snow. Moderate to strong northwest winds shifting southwest.Wednesday: Cloudy with another round of flurries bringing another 5-10 cm of new snow, continuing overnight. Strong southwest winds. Alpine high temperatures around -4.Thursday: Cloudy with continuing flurries bringing an uncertain 10-30 cm of new snow, continuing overnight. Strong to extreme southwest winds. Alpine high temperatures around -2 as freezing levels climb to 1800 metres.Friday: Mainly cloudy with scattered flurries and a trace to 5 cm of new snow. Moderate west winds. Alpine high temperatures around -9 as freezing levels return to valley bottom.

We have a social media report describing an avalanche involvement that resulted in the partial burial of one individual in the Allan Creek area on Sunday. The rider's use of an airbag pack appears to have aided a quick and successful companion rescue effort. Clearing weather on Sunday also allowed for observations of numerous natural storm slab releases in the Cariboos. These reached up to size 3 (very large) and were focused on north aspects as well as steep alpine features.Prior to the storm, a few large (size 2-3) natural persistent slab avalanches were reported last Sunday. These avalanches were reported on south aspects in the alpine. Numerous persistent slab avalanches (up to size 3) were reported on all aspects in the third week of December. The persistent slabs were 50-150 cm thick and likely failed on the early December weak layer. The inability of our recent storm to produce a renewal of persistent slab activity suggests that this layer may finally have become dormant.

Saturday's storm brought about 35-45 cm of new snow to the region. In many areas, the new snow overlies a layer of surface hoar that was reportedly widespread at treeline and above in advance of the storm. This interface has seen improving strength over the last day or so. It covers a few cm of storm snow from light snowfalls in days prior to the storm.Avalanche activity on the 110-180 cm deep weak layer that formed during the dry spell in early December has greatly diminished over the last week. This layer is composed of weak facets, surface hoar, and a sun crust on steep south-facing slopes. It is believed to be trending toward a dormant state after the loading test brought by Saturday's storm failed to produce consistent reports of avalanches 'stepping down'. Places that might still challenge this assumption of dormancy would be steep north and east facing slopes between 1900-2300 m and steep south-facing slopes in the alpineA weak layer from mid-November and a crust that formed in late October are found near the bottom of the snowpack. The probability of triggering these deeper layers is low, but the most suspect areas would be shallow spots in steep, rocky terrain.