Carefully assess wind-affected terrain before committing to a feature. It may be possible to trigger wind slabs near ridge-crests and steep roll-overs. In the north of the region, monitor for surface hoar underneath the storm snow.
15-30 cm of recent snow has been redistributed into wind slabs at upper elevations. Strong winds have shifted from the southwest to the northwest making it possible to trigger these wind slabs on a range of aspects. Cornices are large and looming and may trigger avalanches on slopes below.
In the north of the region, there is uncertainty surrounding the presence of surface hoar at the recent storm snow interface, particularly around treeline elevations. If you are increasing your exposure to avalanche terrain, carefully evaluate the bond of the new snow to the crust.
Monday night: Mostly cloudy, moderate northwest winds, treeline low temperatures near -13 C, freezing level at valley bottom.
Tuesday: Mix of sun and cloud, light northwest winds, treeline high temperatures near -11 C, freezing level rising to 300 m.
Wednesday: Cloudy, isolated flurries with a trace of snow, moderate southwest winds increasing to strong and becoming west at upper elevations, treeline high temperatures near -12 C.
Thursday: Cloudy, isolated flurries with a trace of snow, moderate west winds, treeline high temperatures rising to -6 C in the late afternoon, freezing level rising to 500 m.
Wind slabs and lingering storm slab avalanches may remain sensitive to human-triggering on Tuesday. Cornices could be reaching their breaking point and could act as triggers on slopes below.
On Sunday, observers in the north of the region reported large (size 2) natural avalanches releasing in the storm snow near Dark Side Lake (see this MIN and this MIN). In the south of the region, operators reported several small (size 1) wet loose avalanches releasing naturally at lower elevations.
Over the weekend, the mountains picked up 15-30 cm that fell as snow above 1400 m along the Duffey and above 1700 m near the Coquihalla. Below these elevations, the recent snow has cycled through a melt-freeze cycle and the hazard can be treated as low.
Strong to extreme southwest winds during the storm have since become moderate from the northwest and have redistributed the recent snow into wind slabs across a range of aspects at upper elevations. Monitor for changing slab conditions as you move into wind-exposed terrain.
The recent snow is settling and stabilizing; however, there is lingering uncertainty as to whether a layer of surface hoar may sit above a crust. This layer is most likely to be preserved in sheltered areas at upper treeline elevations, particularly in the northern half of the region near Pemberton. If you are increasing your exposure to avalanche terrain, carefully evaluate the bond of the new snow to the crust.
Deeper in the snowpack, it is possible to find a crust/facet layer from December that is buried down 100-150 cm. This layer is most prominent between 1700-2100 m and is currently classified as dormant; although large loads such as a cornice failure or avalanches in motion may still be able to trigger avalanches on this layer.
