Slab avalanches in steep terrain are still likely following the recent large storm, especially in wind-affected terrain. Conservative terrain choices are recommended.
Summary
Confidence
Moderate - Due to the number and quality of field observations
Weather Forecast
SATURDAY: Flurries with accumulations of 5 cm, moderate north winds, alpine temperatures around -12.SUNDAY: A mix of sun and cloud, moderate northeast winds, alpine temperatures around -18.MONDAY: A mix of sun and cloud, light northeast winds, alpine temperatures around -20.
Avalanche Summary
On Friday, avalanche reports were limited to a single size 4 natural avalanche, with no details about the sliding layer. I suspect smaller (size 2) avalanches were relatively widespread during the storm on Thursday and into Friday morning.Expect storm slab activity to continue into the weekend and be extra touchy in wind affected terrain. Triggering persistent slab avalanches also remains possible in thin snowpack areas.
Snowpack Summary
Between 30 and 60 cm of new low density snow has fallen over the past week. In higher elevation terrain, moderate to strong winds have promoted slab formation on lee and cross-loaded features. In sheltered areas and lower elevations, the low density snow has only just begun to show signs of consolidation into soft slab. A mid-December interface can be found buried 65-100 cm deep and consists of faceted (sugary) crystals and/or surface hoar. Recent tests suggest the the new snow is generally well bonded to this interface in most areas, but since the layer has still been reactive in some snowpack tests it should be investigated before pushing into steeper terrain. The lower snowpack is well consolidated and features a thick rain crust near the ground.
shorton,
Avalanche Canada
