Wind slabs will continue to build in steep exposed terrain and deeper buried weak layers are demanding careful terrain selection right now.
Recent strong southerly wind formed wind slabs in lee terrain. Keep in mind that a wind slab release could also act as a trigger for the deeply buried late-December weak layer.
Triggering persistent slab avalanches remains possible due to several weak layers in the top metre of the snowpack. Facet layers are the primary concern in alpine terrain, while preserved surface hoar layers are the concern in treeline terrain.
A very large (size 3) persistent slab avalanche was remotely triggered on Sunday. This avalanche failed on a 50 cm deep facet layer and released on a northeast aspect at 1900 m. We continue to get evidence that this persistent slab can be easily triggered by riders in specific areas. There was also a report of a size 2 persistent slab avalanche on a west aspect at 1700 m on Tuesday.
Otherwise, there were several reports of smaller (size 1 to 2) wind slab avalanches over the weekend, primarily occurring on north-facing aspects.
Recent moderate to strong southerly wind formed wind slabs in lee terrain features near ridges. Exposed solar aspects may have formed a surface crust.
Several persistent weak layers may be found in the top meter of the snowpack. These include a surface hoar layer buried on Dec 28 found 40 to 60 cm deep and a facet layer buried on Dec 23 found 60 to 100 cm deep. In alpine terrain, triggering one of these layers is most likely on steep rocky slopes where they present as facets. In treeline terrain, the layers are most likely triggered on steep slopes in open trees where they present as preserved surface hoar.
Wednesday Night
Mostly cloudy with isolated flurries. Moderate south winds. Treeline high temperatures around -6 °C.
Thursday
Flurries through the day, accumulation up to 5cm. Moderate southeast winds. Treeline high temperatures around -4.
Friday
Mainly cloudy with flurries, accumulation 3-8cm. Light to moderate southeast winds. Treeline high temperatures around -5.
Saturday
Mainly cloudy with flurries, accumulation 3-5cm. Moderate to strong south winds. Treeline high temperatures around -2.
More details can be found in the Mountain Weather Forecast.
