Watch for pockets of stiff wind slab at upper elevations from recent northerly outflow winds. These slabs have formed in atypical areas and could be particularly reactive where they overlie a slick crust.
Northerly outflow winds are redistributing available snow into fresh wind slabs in lee south aspect terrain. Wind slabs may be reactive to human triggering where they overlie a slick crust. Seek out sheltered terrain where you can avoid wind slabs and find good riding.
Last Wednesday, we received a MIN report of a skier accidental avalanche from Nak Bowl. The avalanche happened when skiing over a convexity and likely released on a crust below the storm snow. A natural size 2.5 wind slab avalanche was also reported from Nak Peak area. This avalanche is suspected to have stepped down to deeper layers. Several loose avalanches were observed up to size 2 on south aspects from solar input and elevated freezing levels.
On Friday and Saturday, several size 1 loose wet avalanches were observed on steep solar aspects with sun and warm temperatures.
Looking forward to Monday, riders should be cautious around pockets of stiff wind slab in the alpine and treeline. These slabs may fail easily where they overlie a slick crust and will be in more atypical locations, as northerly winds have created a reverse-loading pattern.
Thank you for all the MINs, please continue to share any observations or photos on the Mountain Information Network.
The past week's storm delivered 30 to 40 cm of new snow. Northerly outflow winds have affected open areas in the alpine and treeline, souring windward slopes and redistributing this storm snow into pockets of stiff wind slabs in lee areas. A crust exists on the surface at lower elevations and on steep solar aspects to 1800 m.
Generally, the mid and lower snowpack is well-settled. Weak layers exist within the mid and lower snowpack but the thick crusts sitting above them make triggering avalanches on these layers unlikely.
Snowpack depths are 150 to 200 cm at treeline and taper rapidly below 1500 m.
Sunday night
Clear. Alpine temperatures drop to a low of -13 °C. Light ridge wind from the north. Freezing level at valley bottom.
Monday
A mix of sun and cloud. Alpine temperatures reach a high of -7 °C. Ridge wind light from the north. Freezing level at valley bottom.
Tuesday
Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -5 °C. Mostly light ridge wind occasionally gusting to 40 km/h from the southwest. Freezing level at valley bottom.
Wednesday
Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -3 °C. Ridge wind 30 km/h occasionally gusting to 50 km/h from the southwest. Freezing level 600 metres.
More details can be found in the Mountain Weather Forecast.
