Watch for the formation of fresh wind slabs in exposed terrain as southwest wind picks up ahead of the next storm on Thursday. Snow amounts appear modest for Thursday, but watch for hazard to increase through the day, especially in areas that receive more than 20 cm of new snow.
Time and relatively cool temps are likely tempering reactivity of wind slabs formed over the weekend, but a fresh round of wind slabs will likely form Thursday as southwest wind picks up ahead of the next storm.
The early December crust can be found down 80 to 150 cm below the surface. While activity on this interface has really tapered off, it makes it difficult to have much confidence in stepping out into bigger terrain as avalanches failing on this layer have the potential to be large and destructive.
A storm impacting the region offers a nice refresh of cold snow accompanied by strong wind largely out of the south.
WEDNESDAY NIGHT: Freezing level at valley bottom, trace of snow possible, light variable wind.
THURSDAY: Overcast, freezing level at valley bottom, moderate to strong wind largely out of the southwest, snow beginning in the morning, 2 to 8 cm expected during the day with another 10 to 20 cm expected Thursday night.
FRIDAY: Overcast, freezing level at valley bottom, strong southwest wind, 5 to 15 cm of snow possible.
SATURDAY: Broken cloud cover, freezing level at valley bottom, moderate to strong west wind, 1 to 3 cm of snow possible.
Avalanche activity in the storm snow was diminished Tuesday, but avalanche control work produced avalanches to size 1.5 that were most prevalent in wind loaded upper elevation terrain features.
Lots of natural (and a few human triggered) storm slabs and loose dry avalanches to size 2 were observed Monday, primarily on northeast facing terrain.
In the South Columbias, the only reported activity on the early December crust/facet interface in the last week was a natural size 2.5 avalanche that released in a shallow rocky northeast facing feature at 2300 m. The North Columbia also has very limited recent avalanche activity on the crust, but it has been quite a bit more active in the regions to the south and east, more details and photos of that activity can be found here.
The weekend storm produced 20 to 50 cm of storm snow accompanied by wind that was quite variable, but mainly out of the south. Early reports from folks exploring in the alpine report that there was less wind loading than expected.
We're actively monitoring the early December crust. In some places it's scoured and on the surface, while in wind loaded terrain features it can be found as deep as 150 cm below the surface. It consists of faceted grains above a bulletproof crust formed by the Atmospheric Rivers of early December. Avalanches failing on this interface have the potential to be very large.
