We're into a tricky period as a critical amount of storm snow settles (into a slab) and sits on a buried weak layer. Keep your terrain choices on the conservative side until conditions stabilize.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Dry with gradually warming alpine temperatures during the week. Cold in the valley bottoms. WEDNESDAY: Cloudy with sunny breaks. Ridge wind light west. Alpine temperature -5. Freezing level surface.THURSDAY: Mix of sun and cloud. Ridge wind light southwest. Alpine temperature -5. Freezing level surface.FRIDAY: Cloudy with isolated flurries. Ridge wind light west. Alpine temperature -3. Freezing level surface.
Avalanche Summary
We've had several natural avalanches (and the greatest concern) between 1600m and 1800m on steep or open glades on all aspects... this is where the mid December layer has been most active. On Tuesday we had reports of several small loose avalanches triggered by the sun and warmer temperatures in the alpine. On Sunday we had reports of small features being reactive to sled cutting. See
here for the MIN report - great information from a low-consequence slope. On Sunday, an explosives-triggered Size 2.5 persistent slab avalanche was reported on a south east aspect at 1700m near Fernie, running on the mid-December surface hoar layer (down 65cm in that location).
Snowpack Summary
The mid-December layer (with variable distribution, but commonly found between 1600m and 1800m) is now buried 40-70 cm below the surface. This layer includes crusts on south and west facing slopes and feathery surface hoar in sheltered areas at and below treeline, and has been producing moderate, sudden results in recent snowpack tests.At higher elevations, winds (at times strong from the south west) have modified the snow pack, creating an "upside-down" slab layer with stiffer snow on top of softer snow.The lower snowpack is generally well settled with a thick prominent crust that was buried near the end of November.
mgrist,
Avalanche Canada
