A persistent weak layer remains the primary concern for the region, especially at treeline.
Don't let your guard down, choose conservative terrain where you observe signs of instability.
Triggering of this problem is moving into the low probability, high consequence realm especially in and around the Lizard Range. In the Flathead signs of instability are more frequent, with more recent avalanche activity.
Persistent slab avalanches have been reported almost daily for the past week, including remote triggers.
The upper snowpack structure has weak layers of concern that remain reactive to human-triggering.
A weak overnight refreeze of moist surface crust may break down throughout the day. The crust can be found on solar aspects, and most areas at treeline and below.
Multiple weak layers of surface hoar and/or crust–facet combinations may be present within the upper meter of the snowpack. The most reactive layer, formed in late January, is buried 40–90 cm deep. Recent avalanches have primarily failed on this surface hoar layer, particularly in steep, sheltered terrain at treeline and below.
While this layer has shown reduced reactivity near the ski hill and in the Lizard Range, riders are still sporadically triggering it across the forecast area.
Thursday Night
Clear skies. 40 km/h west ridgetop wind. Treeline temperature -4 °C.
Friday
Mix of sun and clouds. 40 km/h west ridgetop wind. Treeline temperature -4 °C.
Saturday
Mostly cloudy. 2 to 4 mm of precipitation as snow or rain at treeline. 60 km/h west ridgetop wind. Treeline temperature -2 °C. Freezing level 1800 m.
Sunday
Mostly cloudy. 10 to 25 mm of precipitation as snow or rain at treeline. 60 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 2100 m.
More details can be found in the Mountain Weather Forecast.
