Watch for recently formed wind slabs in exposed high elevation terrain features.
Large cornices are reported to have become weak with the recent mild conditions and should be avoided when travelling on or below ridge crests.
Recent moderate to strong winds may have formed wind slabs in the high alpine where there was still dry snow available for transport. With only limited snow expected to be available for transport, any wind slabs that formed are expected to be small.
Large cornices have become weak with recent mild temperatures and are expected to remain weak on Thursday. This MIN post from Tuesday shows examples of cornices in the region including one which failed naturally.
Unsettled conditions are expected for Thursday before a weak storm system arrives on Friday.
Wednesday night: Light snowfall 1-4 cm, moderate W winds, treeline low around -5 °C.
Thursday: Mainly cloudy with periods of sun in the morning and a chance of isolated flurries, light to moderate NW winds, freezing level around 1000 m.
Friday: Snowfall 5-10 cm, moderate to strong SW winds, freezing level around 1200 m.
Saturday: Mainly cloudy with a chance of both sunny breaks and flurries, moderate SW winds, freezing level around 1100 m.
On Tuesday, the Avalanche Canada field team reported a natural size 2 cornice release which was observed on a northeast aspect at 1750 m. In the far north of the region, some additional cornice releases were observed, one of which triggered a slab on the slope below. At lower elevations in the south of the region, explosives triggered loose wet avalanches up to size 2. A natural size 2 icefall was also reported.
On Monday, several small wet loose avalanches were observed on steep solar terrain in the region.
A few centimetres of new snow is expected to have buried a widespread supportive crust which extends into the lower alpine on all aspects and the high alpine on sun-exposed aspects. Wind slabs may be found at high elevations on north and east aspects. Large overhanging cornices have also been observed in the region recently which may remain weak with the current mild conditions.
A couple of layers of weak crystals in the upper snowpack appear to be bonding according to recent observations and snowpack tests. Additionally, we suspect that the surface crust will help bridge these layers, further decreasing their likelihood of triggering older persistent weak layers.
