Start small and gather information about storm snow's reactivity before committing to bigger features. Avoid generalizing observations to places where surface hoar may be buried.
Reports show the surface hoar buried 60 to 100 cm deep is becoming harder to trigger, but recent loading may have increased this layer's sensitivity. Triggering this layer is most likely at higher elevations.
Storm snow may remain reactive to human triggers, particularly where wind loaded (think leeward terrain at ridgecrest) and where it overlies weak surface hoar (think sheltered mid-elevations).
Visibility was limited on Saturday but we still got lots of avalanche reports connected to the 30-60 cm of new snow that fell in the region. Here's a report from the action west of Revelstoke.
Professional reports echoed this MIN with a mix of numerous storm slab and dry loose releases, mainly to size 1.5 (small). Persistent slabs didn't figure into these reports. Did the storm trigger any? Wider observations with clearer skies may tell us.
30-60 cm of new snow blanketed the region in Saturday's storm. Deeper and more reactive deposits are found in east facing terrain features. The new snow has buried an aspect and elevation-dependent mix of crusts, surface hoar, and facets.
A crust formed by the early December rain event is found roughly 70 cm deep, and a layer of surface hoar is found 60 to 100 cm deep.
Where the crust is thick and strong it makes triggering the surface hoar layer less likely. Triggering remains a concern at higher elevations where the crust is less prominent.
The lower snowpack is variable throughout the region and weak basal facets are likely to be found on the ground in shallow snowpack areas.
Sunday night
Diminishing cloud. Northwest alpine wind shifting southwest, 5-15 km/h.
Monday
Increasing cloud with a possible trace of new snow by end of day, increasing overnight. Southwest alpine winds 5-15 km/h, increasing. Treeline temperature -10 °C.
Tuesday
Cloudy with continuing snowfall bringing 10-20 cm of new snow, continuing overnight. Southwest alpine winds 20-50 km/h. Treeline temperature -7 °C.
Wednesday
Decreasing cloud and easing flurries bringing another 5-15 cm of new snow, including overnight amounts. Northwest alpine wind, 5-15 km/h. Treeline temperature -12°C.
More details can be found in the Mountain Weather Forecast.
