Hazard remains HIGH on Wednesday as the storm ends. Tricky conditions are expected to persist for the next few days.
Summary
Confidence
Fair
Weather Forecast
The storm conditions should end on Wednesday morning. Overnight Tuesday, the region is expected to see another 10-20mm of precipitation with moderate-to-strong SW alpine winds. On Wednesday, alpine winds should progressively ease and precipitation should taper off in the morning. Freezing levels are expected to rise to over 2000m in the south of the region (lower in the north of the region). A temperature inversion may trap cold air in the valleys. Similar conditions are expected on Thursday and Friday with freezing levels above 2000m and a temperature inversion, light alpine winds, and generally dry conditions. The warm air is currently forecast to break down on Saturday.
Avalanche Summary
On Tuesday, several natural size 2 avalanches were reported in the Terrace area. On Monday, natural and explosive triggered avalanches up to size 2.5 were reported in the central part of the region. Natural storm and wind slab avalanches are expected to continue on Wednesday and the potential for human triggering remains very high.
Snowpack Summary
Storm snow amounts vary across the region. Since the weekend, southern areas received 50-80cm of new snow and the north probably around half that. Strong winds are one common theme in all areas though. Ridge winds were cranking from the SE-SW stripping windward slopes bare and probably forming hard or dense wind slabs in lee and cross-loaded areas. A buried surface hoar layer down around 70cm may be more prevalent in northern sections like Bear Pass and Ninginsaw Pass. The mid December crust can be found down around 1m and is sandwiched with facets and surface hoar. The November crust down near the bottom of the snowpack is generally well bonded but is still reactive in some test profiles. The deeper snowpack weaknesses could 'wake up' with heavy loading from new snow and wind.
rbuhler,
Avalanche Canada
