Dangerous avalanche conditions are expected.
Stick to non-avalanche terrain or very small features with limited consequences.
Persistent weak layers of surface hoar/facets or crust remain a concern in the upper 50 - 100 cm. Storm slab avalanches could step down to these layers, forming very large avalanches.
Storm slabs will be building through Sunday and expected to be most reactive on north through east facing wind-loaded slopes at upper elevations.
Wet loose avalanches will be very likely during periods of sun or when the snow surface is moist or wet. Avoid overhead hazard from steep sunny slopes.
Reports have been limited during the stormy period, but widespread avalanche activity with slabs up to size 3 has been reported in the southern parts of the region. Several cornice collapses, some of which triggered slabs below have also occurred. On Friday, a very large size 3 persistent slab was observed near Blue River on a south-facing treeline slope.
With recent snow, sun and warming in the forecast, we expect to see widespread and large avalanche activity on Monday.
Up to 35 cm of snow has accumulated since Sunday, building widespread storm slabs. Sunny slopes and lower elevations will have moist or wet snow. Sun and warming on Monday are expected to make the new snow particularly unstable. There is a significant concern for storm slabs to step down to deeper persistent weak layers. These consist of surface hoar, facets, or a crust:
The early March layer down 50 - 100 cm. This is the primary weak layer of concern.
Mid-Feb & Late-Jan layers down 80 - 180 cm. Concern for these is in shallow or rocky areas. Otherwise, they are unlikely to trigger without a significant load like a cornice failure or storm slab in motion.
Sunday Night
Mostly cloudy with 10 to 25 cm of snow / possible rain below 1300 m. 40 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level around 1500 m.
Monday
Early morning flurries up to 5 cm, then clearing and sunny. 20 to 30 km/h west ridgetop wind. Treeline temperature 0 °C. Freezing level rising to 1900 m.
Tuesday
Cloudy with 1 to 5 cm of snow / possible rain below 1600 m. 15 to 20 km/h south ridgetop winds. Treeline temperature +1 °C. Freezing level rising to 1900 m.
Wednesday
Cloudy with 10 to 20 cm of snow / possible rain below 2500 m. 25 to 30 km/h southeast ridgetop winds. Treeline temperature +4 °C. Freezing level rising to 2700 m.
More details can be found in the Mountain Weather Forecast.
