Pockets of wind slab are the primary concern for human triggering today. Take the time to dig down and test the November 26th crust before committing to larger slopes.
Weather Forecast
A frontal system moves in this afternoon bringing 6cm of accumulation today and 8cm overnight. Winds will be moderate from the SW and freezing levels will hover around 1100m. A ridge of high pressure is expected to build on Sunday, deflecting moisture to the north and leaving Rogers Pass with mainly dry conditions for the rest of the week.
Snowpack Summary
The November 26th crust layer is easily identified down 65cm. It separates the moist and warm lower snowpack from the cold and dry upper snowpack. Stability tests from yesterday show that new snow is bonding well to the crust at tree line. The recent storm snow is variable at higher elevations and may include reactive pockets of wind slab.
Avalanche Summary
Five size 2 natural avalanches were observed in the highway corridor from very steep, wind-loaded start zones on the north face of Mt Macdonald. Steep, wind loaded features are the number one avalanche concern heading into today.
Confidence
Forecast snowfall amounts are uncertain
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.