A widespread avalanche cycle is ongoing, with large avalanches running to the end of their runouts. Areas exposed to overhead terrain, such as traveling up towards Balu Pass, are not recommended. Minimize your exposure and use safe travel practices.
Weather Forecast
Snowfall rates should off today, but windloading will continue with moderate to strong W'ly winds. There should be clearing later today, with alpine temps of -4. Wed and thursday should be dry with a mix of sun and cloud, temps of -15 to -20 and moderate to strong winds shifting to the NW.
Snowpack Summary
Hourly snowfall rates of up to 4cm an hour overnight, magnified by SW winds transporting snow, rapidly loaded the snowpack. Snowpack tests yesterday found several reactive storm snow instabilities. The Nov 12 surface hoar layer, now down ~1m, gave sudden planar results on a SE aspect at 2050m. All reports from the field indicated slabby conditions.
Avalanche Summary
A widespread natural avalanche cycle started overnight with heavy snowfall and moderate to strong winds. Numerous size 2.5-3 avalanches occurred in paths along the highway east and west of Rogers Pass. Most notably, Laurie, Junction E, and Crossover slidepaths had size 3 avalanches running into the avalanche fans with some to the end of the runout.
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.