Pay attention to conditions that change with exposure to wind. Maintain margins around wind-drifted features, particularly near ridges and roll-overs.
Strong southwest winds and recent snow have formed wind slabs in lee terrain features at upper elevations that may remain possible to trigger. With winds shifting to the southeast, there is potential for fresh slabs to build in a cross-loaded pattern.
A short burst of southeast wind on Monday
Sunday night: Cloudy, 5-15 cm of snow above 500 m, winds shifting to southeast and increasing to moderate, treeline temperatures near -4 C.
Monday: Cloudy, 5-15 cm of snow above 600 m, moderate southeast winds easing to light, treeline temperatures near -4 C.
Tuesday: Mainly cloudy, light southwest winds, treeline temperatures near -6 C, freezing level around 400 m.
Wednesday: Cloudy, 5-15 cm of snow over 500 m, moderate south winds, treeline temperatures near -4 C.
A natural avalanche cycle occurred in the early morning hours on Saturday. We received a report of several small (size 1) avalanches releasing 20 cm deep in the storm snow in the North Shore Mountains.
Bands of localized precipitation are forecast to bring another 10-30 cm of snow to the mountains by late Monday. A shift in wind direction from the southwest to southeast may form fresh wind slabs in a tricky cross-loading pattern at upper elevations. Pay attention to changing conditions as you move into wind-exposed terrain. It may be possible to trigger wind slabs in lee terrain features, such as down-wind of ridges and roll-overs.
An impressive storm over the weekend brought 50-90 cm of snow to the mountains. A gradual rise in temperature during the storm formed a thin crust layer that can be found in areas up to 1400 m. An additional 30-60 cm of snow has accumulated above this mid-storm crust layer since temperatures have cooled. Strong southwest winds
Below the early December crust layers, the snowpack is generally well-settled. With this storm event, a greater number of areas below treeline are meeting threshold snow depths for avalanches.
