Danger will increase as snow accumulates above a slippery crust, especially on wind-loaded slopes near ridges.
A frontal system crossing the region will form unstable wind slabs on Wednesday. These conditions will most likely be found on the leeward side of ridges and could be poorly bonded to the underlying crust.
A cold front will bring gusty winds and 10-25 cm of low density snow on Wednesday.
TUESDAY NIGHT: Cloudy with flurries bringing 5-10 cm of low density snow in the south of the region and 10-15 cm in the north near Revelstoke, moderate with from the southwest with gusts to 70 km/h, treeline temperatures around -8 C.
WEDNESDAY: Flurries continue with 10-20 cm of low density snow, moderate to strong wind from the west, treeline temperatures around -8 C.
THURSDAY: Another 5-10 cm of low density snow by the morning then mostly cloudy skies throughout the day, light to moderate wind from the west, treeline temperatures around -12 C.
FRIDAY: Mostly cloudy, no significant precipitation, light wind from the southwest with some moderate gusts, treeline temperatures around -10 C.
Avalanche activity since the last atmospheric river has mostly been limited to small (size 1) avalanches. Most have been loose snow avalanches above the crust as well as a few stiffer wind slabs at upper elevations. One large (size 2) naturally-triggered wind slab was observed over the weekend on a steep south-facing slope in the alpine.
Be on the lookout for low density snow becoming a more cohesive slab above the crust, especially in wind-affected areas.
With 10-25 cm of fresh snow in the forecast, we can expect a total of 20-50 cm of low density snow above the crust that formed during last week's atmospheric river. This crust extends into the alpine (as high as 2400 m), and there is some concern about the bond of the recent snow to this crust. The surface snow should remain loose in sheltered terrain, but with strong winds in the forecast, we expect extensive blowing snow and the formation of fresh wind slabs at upper elevations.
The snowpack structure is relatively simple beneath the crust. Treeline snow depths are roughly 100-200 cm with an early November crust layer in the lower snowpack. While some faceting has been reported around this crust, it does not appear to be problematic at this point. The snowpack decreases rapidly below 1600 m.
