The December crust is shallow enough to easily investigate its bond to overlying snow. Slabs over weak grains on the crust may be surprisingly reactive, especially in shallow, rocky areas.
Continuing light snow and southerly winds are promoting slab formation on an ongoing basis.
Many older slabs have likely stabilized, but keep wide safety margins near shallow, rocky start zones, where slabs may overlie faceted snow.
Skiers remote-triggered a large wind slab from 100 m away in the Little Simpson area on Hudson Bay Mountain on Monday. It failed on faceted snow, a reminder that weak grains may extend the reactivity of wind slabs.
Up north, a 40 cm-deep layer of surface hoar on the early-December crust was recently reactive to skiers in the Ningunsaw area. The Ningunsaw slide path produced size 2.5 and size 3 avalanches on Monday and Tuesday night.
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Light new snow amounts have been combining with an aging wind slab problem and with otherwise heavily wind affected surfaces in the alpine and at treeline.
A crust from early December is the most prominent layer in the snowpack and is now buried 30 to 50 cm deep. In some areas, a weak layer of surface hoar may found at this interface. Faceted snow is perhaps more likely to find here and poses a similar problem.
The are no layers of concern below the early December crust.
Friday Night
Partly cloudy. 15 to 30 km/h south ridgetop wind. Treeline temperature around -5 °C.
Saturday
Mainly cloudy. 10 to 15 km/h southeast ridgetop wind. Treeline temperature -7 °C.
Sunday
Mainly cloudy with isolated flurries continuing from overnight. Minimal accumulations. Calm to 10 km/h variable ridgetop wind. Treeline temperature -6 °C.
Monday
Mainly cloudy with isolated flurries. 5 to 10 km/h southeast ridgetop wind shifting southwest. Treeline temperature -6 °C.
More details can be found in the Mountain Weather Forecast.
