Ongoing moderate to strong winds at higher elevations are expected to continue to develop wind slabs where there is still loose surface snow available for transport. Lingering hard wind slabs are most likely to be triggered in steep, unsupported, and/or convex terrain features.
Recent strong winds have formed slabs in exposed high elevation terrain. Wind slabs have been most reactive where they overlie a thin crust. Expect these lingering wind slabs to remain reactive to human triggering on steep, convex and/or unsupported terrain features. Ongoing slab development is expected where there is still loose surface snow available for wind transport.
The ridge of high pressure is currently forecast to break down on Friday before the next storm system arrives Friday night.
Wednesday Night: Partly cloudy, moderate SW wind, treeline temperature around -8 °C.
Thursday: Mainly sunny with a chance of valley cloud in some areas, moderate to strong SW wind, treeline high around -3 °C.
Friday: A mix of sun and cloud, strong SW-W wind, treeline high around -3 °C.
Friday night and Saturday: Snowfall up to 25 cm, strong SW wind, treeline high around -2 °C.
On Tuesday, explosives triggering numerous wind slabs up to size 3 in the south of the region. Some of these were failing down to the bedrock in extreme terrain features. A natural size 2 cornice-triggered wind slab was observed north of McBride.
No new avalanches were reported on Monday. A variety of natural and human-triggered wind slab avalanches were observed over the weekend.
Recent strong wind has hit the region hard, stiffening 20-35 cm of recent snow in open areas at treeline and throughout the alpine. Gusty winds have loaded terrain further downslope than usual. Strong sun from Monday has produced a thin sun crust on solar aspects. Surface hoar was noticed in sheltered areas up to the alpine. Cool overnight temperatures have produced a surface crust at lower elevations up to 1500 m. See our field team photos from Anzac on Sunday.
A thin crust is found under the recent snow, which was responsible for wind slab activity over the past weekend. Another crust is found down 70 cm but has not shown recent reactivity. The lower snowpack is generally strong and bonded, with one or multiple crusts near the ground. We suspect the lower snowpack could be weak in shallow rocky wind-affected slopes east of the divide.
