Avalanche Forecast

Moderate

We don't yet have reports of avalanche activity from Friday's snowfall in this part of the Columbias, but the mid-November interface described in our snowpack summary has been producing plenty of avalanches and signs of instability with each of the last couple of storms in our adjacent central Columbia region.

With a bit more new snow Saturday night adding to the snow settling on this layer, we may be reaching a threshold where instability begin to expand out from wind loaded areas to form a more widespread storm slab problem.

Please share your observations to the MIN!

Another 5-10 cm of new snow should arrive in the region by late morning Sunday. The new snow adds to a settling 20 to 30 cm of snow from storms on Tuesday and Friday night.

The new and recent snow collectively overlies a variety of surfaces that formed mid-November, including weak surface hoar in sheltered treeline terrain, sugary faceted grains, a thin crust on steep solar aspects, or bare ground in wind-exposed terrain. In some areas this interface may present as a thin temperature crust that is more uniform across elevations and aspects.

Average snowfall depths are around 20 to 50 cm below treeline and 80 cm in the alpine.

Saturday night

Cloudy with flurries. Moderate southwest winds.

Sunday

Cloudy with continuing flurries bringing 5-10 cm of new snow, including overnight amounts. Becoming a mix of sun and cloud. Moderate northwest winds easing over the day. Treeline high temperatures around -5 C.

Monday

Mainly clear. Light northeast winds. Treeline high temperatures around -8 C.

Tuesday

Clear, becoming cloudy in the afternoon. Light south winds increasing in the afternoon. Treeline high temperatures around -12.

More details can be found in the Mountain Weather Forecast.

• Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.