Avalanche hazard is increasing as the storm slab gains cohesion. Avalanches can run far on low elevation surface hoar.
Weather Forecast
A SW flow brings a series of storms over the next several days. Expect light precipitation today with freezing levels around 1500m and moderate to strong SW winds. Precipitation intensifies late this afternoon with up to 12cm of heavy snow overnight. Freezing levels climb to 1700m on Sunday with ongoing light precipitation.
Snowpack Summary
Up to 25cm of heavy storm snow affected by warm temps and wind has formed a soft slab over a widespread layer of large surface hoar. On solar aspects, the surface hoar sits on a sun crust. The Nov 5 surface hoar layer is buried down 80-100cm. On true north aspects, a basal weakness may become unstable with the recent additional snow loading.
Avalanche Summary
Numerous avalanches were observed from the highway corridor east of Rogers Pass, up to size 2.5. Avalanches starting high in the alpine triggered additional slabs at lower elevations. Whumpfing and cracking was observed below treeline.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.