Triggering large persistent slab avalanches remains possible.
Buried weak layers are likely gaining strength but the possibility of triggering a large persistent slab avalanche remains. There are two weak layers, both composed of surface hoar and facets, anywhere from 40 to 150 cm deep. It may be more likely to trigger these layers where they are buried relatively shallow.
A few small to large (size 1 to 2) storm slab avalanches were triggered naturally and by explosives on Friday and Saturday, generally 30 to 60 cm deep within recent storm snow.
Large (size 2 to 3) avalanches occurred within the past week, with some of them stepping down to deeper weak layers. We suspect it is becoming more difficult to trigger these deeper layers, however caution should be taken in challenging or complex terrain given the uncertainty and consequence of large avalanches.
Around 50 cm of snow sits on a hard melt-freeze crust found up to treeline elevations formed by rain on December 26. Moist snow or a surface crust may be found up to around 1600 m on all aspects and up to ridgetop on sun-exposed slopes.
Two deeper layers of surface hoar and facets could still be triggered in specific terrain. These include a 40 to 80 cm deep layer buried mid-December and an 80 to 150 cm deep layer buried mid-November. These layers are generally deeper around Fernie and shallower towards Sparwood and Elkford. The layers may be easier to trigger where they are buried within the top 100 cm of the snowpack.
Sunday Night
Mostly cloudy with trace snowfall, 10 km/h west wind, treeline temperature -6 °C.
Monday
Mix of sun and cloud with no precipitation, 10 km/h south wind, treeline temperature -5 °C.
TuesdayMostly sunny with no precipitation, 10 to 20 km/h southwest wind, treeline temperature -8 °C.
WednesdayCloudy with isolated flurries, 20 to 40 km/h southwest wind, treeline temperature -10 °C.
More details can be found in the Mountain Weather Forecast.
