Watch for isolated pockets of stiff wind slab in the alpine from recent northerly outflow winds.
A surface crust will make for challenging travel conditions but generally safe avalanche conditions.
Northerly outflow winds have created isolated pockets of stiff wind slabs in the alpine. These slabs may be more reactive where they overlie a slick crust and will be in more atypical locations, as northerly winds have created a reverse-loading pattern.
On Friday, thin but reactive size 1 wind slabs were skier-triggered in steep alpine ridgetop features.
As northerly outflow winds increased on Saturday, small, thin wind slab formation was noted in isolated areas in the alpine.
Looking forward to Monday, riders should be cautious around isolated pockets of stiff wind slab in the alpine.
Please continue to share any observations or photos on the Mountain Information Network.
Northerly outflow winds have affected open areas in the alpine and treeline, souring windward slopes and creating pockets of stiff wind slabs in lee areas. A thin breakable crust can be found at or near the surface on all aspects at treeline and above. This crust is thick and supportive below treeline and on steep solar aspects.
A crust from mid-January can be found down 40-70 cm deep. A number of weak layers exist within the mid and lower snowpack but the thick crusts sitting above them make triggering avalanches on these layers unlikely.
The areas of concern in terms of triggering a deeper layer are shallow rocky areas.
Sunday night
Clear. Alpine temperatures drop to a low of -10 °C. Light ridge wind from the north. Freezing level at valley bottom. Alpine temperature inversion.
Monday
A mix of sun and cloud. Alpine temperature inversion. Alpine temperatures reach a high of -6 °C. Ridge wind light from the northwest. Freezing level at valley bottom.
Tuesday
Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -8 °C. Light ridge wind from the southwest. Freezing level at valley bottom.
Wednesday
Mainly cloudy with scattered flurries, 5-10 cm of accumulation. Alpine temperatures reach a high of -4 °C. Ridge wind 25 km/h gusting to 50 km/h from the southwest. Freezing level 800 metres.
More details can be found in the Mountain Weather Forecast.
