Wind continues to be the main driver of the avalanche danger in the region. The wind direction is expected to shift again on Friday and wind slabs should be expected on all aspects in exposed terrain.
Recent strong NE winds have likely formed wind slabs on lee features at treeline and above. These wind slabs are most likely to be found on south and west aspects, but older wind slabs may be found on all aspects.
These wind slabs may remain reactive for longer than normal because they are sitting on weak facets (sugary snow).
One more day under the influence of the Arctic high pressure before a storm system moves inland Friday overnight. The south of the region is currently forecast to receive 20-30 cm by Sunday morning while the north will see substantially less.
Thursday Overnight: Cloudy in the south, clear in the north, light variable wind, treeline temperature around -24 °C.
Friday: Cloudy with sunny breaks, light to moderate W wind, treeline high around -22 °C.
Saturday: Snowfall 10-15 cm in the south, less in the north, moderate to strong SW wind, treeline high around -22 °C.
Sunday: Snowfall 10-15 cm overnight, lingering snow flurries in the morning, strong to extreme SW wind, treeline high around -18 °C.
On Wednesday, explosives triggered a size 2 wind slab in the far south of the region. There has been evidence of a few natural wind slabs in the region which occurred at the beginning of the week.
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!
Recently formed wind slabs are most likely to be found on south and westerly aspects, but older wind slabs may be found on all aspects. These wind slabs may remain reactive to human triggering for longer than normal due to the presence of weak facets (sugary snow) below them.
The base of the snowpack is composed of crusts and weak faceted grains, particularly in thin snowpack areas. While these layers have generally gone dormant in the region, they still have the possibility of waking up with new snow load or warming, and wind slab avalanches may still have the potential to step down to these deeper layers in isolated areas.
