Avalanche danger will rise through the day as new snow and wind form fresh, reactive wind slabs.
Danger will increase throughout the day as snowfall and southwest winds build fresh, reactive wind slabs in lee areas in the alpine and treeline.
Older, hard wind slabs exists below the new snow from easterly outflow winds earlier in the week. These slabs will likely be quite stiff and stubborn to triggering but would be larger and more consequential if triggered.
Friday Overnight: Light snowfall, trace accumulation. Moderate to strong southwest winds. Alpine temperatures around -25 C.
Saturday: Snowing, up to 5cm accumulation. Moderate to strong southwest winds. Alpine temperatures rising to -20 C. Heavier snowfall overnight, with up to 20cm of accumulation.
Sunday: Light snowfall, up to 5 cm accumulation. Moderate to strong southwest winds. Freezing levels rising to 1700m in the afternoon.
Monday: Partially cloudy, isolated flurries. Moderate southwest winds. Freezing levels 500-1000m.
Observations have been limited due to the cold conditions. If you are out in the mountains, let us know what you see by filling out a Mountain Information Network report!
Snowfall and southwest winds will build fresh, reactive wind slabs in lee areas in the alpine and treeline throughout the day.
These fresh wind slabs overlie a previously wind affected surface comprised of old hard wind slabs, sastrugi, and areas stripped back to the ground or old crusts. Near surface faceting above the old surface may increase the reactivity of newly formed wind slabs.
A crust that was formed at treeline elevations and below in early December has been reported in parts of this region. It can be found down 50-100 cm. There have been no recent reports of avalanches on this layer. While the layer is now dormant in the region, a large amount of new snow or warming temperatures have the potential to wake it up, and wind slab avalanches may still have the potential to step down to this layer in isolated areas.
The base of the snowpack is composed of crusts and weak faceted grains, particularly in thin snowpack areas east of the divide.
