630 am update: New snow and wind are elevating avalanche hazard.
Natural and human triggered avalanches can be expected in wind loaded features. This MIN from the Flathead is a great example of the type of terrain where the wind slab problem can be found. Evaluate snow conditions as you transition into open terrain features, and be on the lookout for signs of instability like shooting cracks.
5 to 10 cm of new snow coupled with southwest wind could continue to build wind slabs in lee terrain features. Look for signs of instability like shooting cracks as you approach open terrain features.
A layer of faceted grains near the base of the snowpack remains on the radar for areas of this region where the snowpack is shallow and where a hard melt-freeze crust formed around Christmas doesn't exist. Deep persistent slab avalanches have not been reported in the region for some time, however, the weak snowpack structure in these shallow areas may still be triggered with a heavy load.
Natural and rider-triggered (size 1 to 1.5) wind slabs continue to be reported at treeline and alpine elevations. This MIN from the South Rockies field team is a good example of terrain where wind slabs are more likely to be triggered.
Looking forward, riders could trigger small wind slabs in lee terrain features from the recent snow and sustained southwest wind.
Please continue to share any observations or photos on the Mountain Information Network.
5 to 10 cm overnight will be redistributed by moderate to strong winds developing wind slabs at treeline and alpine elevations. This overlies previous wind slabs that may still be reactive and a melt-freeze crust below 1900 m
The mid-pack is consolidated in the Lizard Range with a robust melt-freeze buried 70 to 90 cm.
Outside of the Lizard Range, the snowpack is shallower and more faceted. In these areas, deep weak layers formed early season are slowly gaining strength but are still a concern, especially in steep rocky terrain features.
Friday Night
Cloudy with overnight snow, 5 to 10 cm of accumulation, 10 to 15 km/h southerly winds, treeline temperatures -2 ºC
Saturday
Mainly cloudy, continued flurries through the morning 2 to 5 cm accumulation, 10 to 20 km/h southwest winds, treeline temperatures -4 ºC.
SundayCloudy with flurries, 2 - 4 cm accumulation, 30 to 40 km/h southwest wind, treeline temperature -5 ºC.
MondayCloudy with flurries, accumulation 2 to 4 cm, 20 km/h southwest wind, treeline temperature -5 ºC.
More details can be found in the Mountain Weather Forecast.
