Snow forecasts are variable for the region. Expect avalanche conditions to become more dangerous throughout the day, especially in areas that receive more than 20 cm of new snow.
The storm crossing the region will build thick and reactive storm slabs. In the north of the region these slabs will build overnight and be reactive first thing Sunday morning, while in the south of the region they will be building throughout the day.
A frontal system crossing the region on Sunday will bring variable amounts of snow at different times of the day.
SATURDAY NIGHT: The storm starts in the north with 10-15 cm of snow overnight and only 5-10 cm in the south, strong south wind, treeline temperatures around -4 C.
SUNDAY: Flurries continue in the north with another 15-20 cm, and build in intensity in the south with 10-25 cm by the afternoon, overall totals from the storm will range from 15-40 cm, strong south wind, freezing level around 1200 m with treeline temperatures around -4 C.
MONDAY: The front may stall over the Cascades and deliver another 10-20 cm of snow while there will just be scattered flurries in the north, light to moderate south wind, treeline temperatures around -4 C.
TUESDAY: Scattered flurries with 5-10 cm of snow, moderate to strong southwest wind, treeline temperatures around -6 C.
Avalanche activity over the past few days has been limited to small winds slabs and dry loose avalanches. However the focus on Sunday will be fresh storm and wind slabs becoming increasingly reactive as the storm intensifies.
15-40 cm of new snow is expected to accumulate by the end of the day on Sunday. This will add to 5-15 cm of recent snow which sits on firm wind affected snow at upper elevations, on surface hoar in some sheltered areas, on a melt-freeze crust below 1600 m, and on a sun crust on south-facing slopes.
In the south, the underlying snowpack is well consolidated. In the north, a melt-freeze crust from early December may be found 100 to 200 cm deep. Recent reports suggest that this layer is gaining strength and it has been unreactive in recent weeks.
