Storm slabs and a persistent weak layer are contributing to unstable snow conditions.
Use conservative route selection and resist venturing into complex terrain
A persistent weak layer of large surface hoar/ facets/ crust from late Januray is buried 40 to 80 cm and remains a significant concern. Avalanche activity has been prevalent on it this week, including some remote triggering.
Up to 40 cm of recent snow combined with strong winds built reactive storm slabs that may need another day to bond. These slabs will be most reactive on lee slopes near ridgetops, and in areas where they overlie a new surface hoar layer.
On Sunday, there were numerous reports of natural, skier-triggered and remote-triggered avalanches across the region in the size 1 to 2 range, with a few as large as 2.5. Some were storm slabs that stepped down to the persistent weak layer. Check out the photos below for some recent reports.
Storm slabs should slowly be gaining strength, but may remain reactive on Tuesday, with potential to step down to the persistent layer.
15 to 40 cm of settling storm snow is covering a new layer of surface hoar and/or a melt-freeze crust in many areas. This may make storm slabs more reactive and resistant to bonding. An additional 5 to 10 cm is forecast overnight and through Tuesday. Southwesterly winds will likely continue building thicker slabs on lee slopes near ridgetops.
At lower elevations and on sunny the snow surface may be crusty.
The late January persistent weak layer, consisting of surface hoar/facets/crust, is buried 40 to 80 cm. It has surprised people with its reactivity over the past week, especially in sheltered treeline features.
The mid and lower snowpack is well settled with no layers of concern.
Monday Night
Cloudy. 0 to 5 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -7 °C.
Tuesday
Cloudy. 0 to 5 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -7 °C.
Wednesday
Mix of sun and clouds. 0 to 5 cm of snow. 20 km/h west ridgetop wind. Treeline temperature -7 °C.
Thursday
Mostly sunny. 40 km/h southwest ridgetop wind. Treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
