Let two words from the field team guide your terrain selection during the warmup: scary snowpack. It's time to minimize your exposure to avalanche terrain and overhead hazards.
Strong alpine winds redistributed much of our loose surface snow into wind slabs in the lee of exposed terrain features in the mid-week. Wind slab releases could step down to a buried weak layer to create a much larger avalanche.
Forecast warming will test 30 cm and 50 cm-deep layers below the recent storm snow as well as the January crust 80 - 130 cm deep. Smaller avalanches may also step down.
These layers have produced numerous recent avalanches.
Solar warming will work to destabilize snow on sun-exposed slopes sheltered from wind. Wet snow may shed naturally or with a human trigger. Loose snow releases may trigger destructive slab avalanches.
A mix of storm, wind, and persistent slab avalanches were observed in the Fernie area Wednesday, from both natural and artificial triggers. They mainly occurred in north-facing alpine terrain and reached size 2.5 with crowns typically ranging from 30 to 50 cm.
A lone natural size 3 deep persistent slab was also observed, apparently failing at the base of the snowpack. It's an occurrence that suggests the possibility of isolated full-depth releases during the warmup.
A melt-freeze crust or moist snow now glazes the surface on solar aspects and, by Friday, below about 2000 m. The depth of affected snow should increase in the coming days, and crust recovery may be weak. This process will affect 30 to 60 cm of settling recent snow that is wind-affected in alpine. About half overlies a crust formed early in the storm. It otherwise overlies faceted snow.
A weak layer of preserved surface hoar or facets from late January is buried 80 to 130 cm deep. This weak layer is expected to stay reactive as warming tests the snowpack. The lower snowpack is generally well-settled, however a lone deep persistent slab observed Wednesday suggests isolated deep releases may occur during the warmup.
Thursday Night
Becoming cloudy. 20 to 40 km/h southwest ridgetop wind, easing. Freezing level falling from 2000 m to 1500 m.
Friday
Mostly sunny. 20 km/h southwest ridgetop wind. Freezing level to 2300 m. Treeline temperature 4 °C.
Saturday
Sunny. 10 to 20 km/h southwest ridgetop wind. Freezing level to 3000 m, rising overnight. Treeline temperature 5 °C.
Sunday
Sunny. 0 to 5 km/h southwest ridgetop wind. Freezing level 2700 m - 3200 m. Treeline temperature 7 °C.
More details can be found in the Mountain Weather Forecast.
