Time to switch your avalanche mindset back to winter. A cold front from the NE brings heavy upslope snowfall which will fall over a slippery crust.
A crust with weak facets above is down 80 to 200 cm. Steep or convex terrain features with a shallow or thin to thick snowpack at treeline and above are the most likely places to trigger this layer.
New snow will likely bond poorly to crusty surfaces. Slabs will be most likely triggered in wind-loaded lees. Loose dry avalanches can be expected in steep terrain where snow hasn't formed a slab.
Loose wet avalanches will become increasingly likely at elevations where precipitation falls as rain. If triggered loose wet avalanches may step down to deeper layers, resulting in very large avalanches.
Numerous naturally triggered loose wet avalanches were reported on sunny aspects at all elevations on Monday. A naturally triggered size 2 wet slab on an east aspect below treeline and a size 2 cornice failure were also reported.
By Tuesday, natural activity had slowed down with only a few size 1 loose wet reported.
10 to 25 cm of cold new snow falls over predominantly crusty surfaces. Below 1500 m, the new snow (or rain) may fall on an already moist upper snowpack.
A widespread, hard crust with facets above is buried around 80 cm deep in the South Rockies and around 200 cm in the Lizard range. It continues to be the primary layer of concern for human triggering of very large persistent slab avalanches.
A cold front from the northeast stalls over the Divide, bringing heavy upslope snowfall to the region on Thursday.
Wednesday night
Cloud with isolated flurries bringing a trace of snow. 10 to 25 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1000 m.
Thursday
10 to 25 cm of snow, with rain below 1300 m west of Elkford and in the Lizard and Flathead areas. 30 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1500 m.
Friday
5 to 10 cm of snow overnight then cloudy. 10 to 20 km/h northeast ridgetop wind. Treeline temperature -8 °C. Freezing level 1000 m.
Saturday
Cloudy with isolated flurries, up to 5 cm. 20 to 30 km/h northeast ridgetop wind. Treeline temperature -10 °C. Freezing level 800 m.
More details can be found in the Mountain Weather Forecast.
