New snow amounts are uncertain for Thursday, so watch for dangerous conditions at higher elevations where heavy accumulations are possible.
New snow will create unstable slabs at upper elevations on Thursday. In areas that get more than 20 cm of fresh snow these will be widespread on all steep slopes, while in areas that receive less snow they will more likely be isolated to wind-loaded slopes.
An intense frontal system is hitting the NW coast and there is high uncertainty about how much precipitation will make it into the inland region.
WEDNESDAY NIGHT: Precipitation intensity peaks overnight with anywhere from 10 to 35 cm of snow possible above 1200 m, strong southwest wind with gusts to 90 km/h.
THURSDAY: Precipitation continues with another 5-15 cm of snow possible above 1200 m and rain below, strong southwest wind with gusts to 70 km/h, freezing level around 1200 m.
FRIDAY: Mostly cloudy with some light flurries, moderate southwest wind with gusts to 50 km/h, freezing level at valley bottom with treeline temperatures around -10 C.
SATURDAY: The next system arrives with 5-10 cm of snow by the evening, strong southwest wind, treeline temperatures reaching -4 C.
There were several reports of reactive storm slab avalanches over the weekend, including this size 2 avalanche triggered by a snow bike in the Microwave area. There was also evidence of a few large (size 2.5-3) avalanches in the Hudson Bay Mountain area that release naturally on north and east facing slopes around 1700 m. These occurred on wind loaded slopes and likely ran down to the early November crust.
Looking ahead, the main concern is new storm and wind slabs developing with the incoming weather.
A frontal system will bring anywhere from 15 to 40 cm of new snow to the region by Thursday evening. The heaviest accumulations are likely in the western areas, but overall the forecast amounts are highly uncertain across the region. What's more certain is that the front will bring strong wind. The combo of new snow and wind will likely form unstable slabs at upper elevations.
Snowpack depths are above average for this time of year, with treeline depths averaging between 100-150 cm. The overall snowpack structure consists of settling storm snow above an early November crust that is now roughly 80-120 cm deep. There has been some evidence of large avalanche running on this crust, but it does not appear to be a major problem at this time. This will be a layer to monitor throughout the season.
