Lookout for stiff wind slabs in the alpine. Likely trigger spots are steep and rocky alpine terrain with a shallow snowpack.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Friday: Cloudy with isolated flurries / Light easterly winds / Weak inversion with a alpine high of -15 C.Saturday: Cloudy with scattered flurries / Light to moderate southerly winds / Alpine high -11 C.Sunday: Mostly cloudy with isolated flurries / Moderate southwesterly winds / Alpine high of -12 C.
Avalanche Summary
No recent avalanche observations have been reported in this region.
Snowpack Summary
Up to 30 cm of recent storm snow has buried old snow surfaces including surface hoar and old, stiff wind slabs. The cold temperatures will have promoted surface faceting, which probably means the top layer of snow is soft in most places. Treeline snow depths around Elkford are only around 60 cm. I suspect they are slightly higher in places like the Flathead, but generally conditions are lean. Threshold snow depths for avalanches have been exceeded in the alpine and at treeline, but not below treeline. In shallow areas, the snowpack is most likely facetted (sugary) throughout, and any crusts have probably broken down already. In deeper areas, you can probably find the mid-November crust buried under half a metre or so of snow.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.