A strong winter storm makes landfall Saturday night and is expected to rage through Sunday night. Travel in avalanche terrain is not recommended Sunday. If you do decide to head out, seek out sheltered, conservative terrain free of any overhead hazard.
I'm expecting to wake up to 15 to 25 cm of new snow Sunday morning, and then another 20 to 30 cm of snow is expected Sunday. A natural avalanche cycle is very likley anywhere there is enough snow to ride, which is expected to encompass all elevations.
An upper low in the Gulf of Alaska will send a frontal wave onto the north coast of B.C. Saturday through Sunday night delivering copious amounts of snow and wind.
SATURDAY NIGHT: Freezing level around 1000 m, strong to extreme southwest wind, 15 to 25 cm of snow expected.
SUNDAY: Overcast, freezing level between 1000 and 1200 m, strong to extreme southwest wind, 20 to 30 cm of snow expected during the day with potential for another 10 to 30 cm of snow Sunday Night.
MONDAY: Scattered cloud cover, freezing level around 500 m, moderate to strong west/northwest wind, 1 to 5 cm of snow expected.
TUESDAY: Overcast, freezing level climbing, potentially as high as 1300 m in the afternoon, strong to extreme southwest wind, 5 to 10 cm of snow possible.
A significant amount of snow and wind are expected as a strong winter storm impacts the region. A natural avalanche cycle is very likely at all elevations as new snow and wind rapidly load the existing snowpack. The exception will be areas where new snow is falling on bare ground.
There have been a few reports of size 1-2 naturally triggered storm slab avalanches during the stormy weather over the past few days (including ones like this from Shames).
On Tuesday, a large (size 2.5) avalanche was triggered with explosives in the northern part of the region. This avalanche failed on weak snow around the crust at the bottom of the snowpack, which is a layer worth monitoring in parts of the region as the season progresses.
Heavy precipitation and strong wind over the weekend will create fresh storm slabs at all elevations.
Over the last week, 30 to 50 cm of snow fell at upper elevations, and a rain crust is extends up to roughly 1000 m. The total snowpack depth is roughly 100 to 150 cm at upper treeline and alpine elevations, and should grow much deeper by Monday. The bottom of the snowpack consists of several thick crusts. There could be weak snow developing around these crusts in colder inland parts of the region.
