If alpine storm snow totals exceed 10cm, the alpine danger rating will likely rise to Considerable.
Summary
Confidence
Fair - Forecast snowfall amounts are uncertain on Saturday
Weather Forecast
FRIDAY NIGHT: 2 to 4mm of precipitation possible, less than 10cm of total snowfall expected. Strong to extreme SW winds.SATURDAY: Freezing level hovering around 1500m. Scattered flurries, less than 5cm of snow expected. Moderate W/SW winds at treeline, strong W/SW winds at ridge-top. Overcast.SUNDAY: Freezing level rising to 1500m. Moderate W/SW winds at treeline, strong W/SW winds at ridge-top. Overcast skies, no significant precipitation expected.MONDAY: Freezing level rising to 1800m. Strong S winds at treeline, extreme S winds at ridge-top. Overcast skies, no significant precipitation expected.
Avalanche Summary
A few natural cornice failures were observed Wednesday & Thursday, but slabs were only triggered in steep, unsupported rocky features and even then had minimal propagation. On Tuesday cornice failure triggered a size 3 avalanche on a North facing feature at 2700m.
Snowpack Summary
The current surface consists of surface facets and surface hoar. Below this is the 15-30cm of new snow that fell last weekend. This snow remains dry on high elevation polar aspects but has turned moist on east and west facing aspects. South facing features are moving into the spring corn cycle. Moist snow exists underneath this most recent storm snow in most of the region.Two significant persistent weak layers composed of crust and facets exist in the snowpack. Although they appear to have gone dormant for the time being, we will continue to monitor them closely. Mid-March is down 40 to 80cm below the surface and Mid-February is down 80 to 200cm. Down at the bottom of the snowpack a weak layer of basal facets exists. Large loads like cornice/ice fall or even sustained warming could initiate an avalanche on this very deeply buried weak layer.
ghelgeson,
Avalanche Canada
