We're still wary of larger features in the backcountry. Everyday this week, we've seen natural activity on the persistent weak layers.
Polar aspects should hold better skiing than sun exposed features at treeline and below.
Watch for windslab development as snow arrives on Friday. Three persistent weak layers formed in January are down 50-90 cm. The biggest concern is triggering these buried suncrusts on steep solar slopes, but weaker facets and isolated surface hoar can be found on the same interface on shaded aspects.
Weak facets and depth hoar are still present at the bottom of the snowpack and inspire little confidence. Be especially cautious in thin snowpack areas, which are likely areas for triggering. Cornices may also trigger this layer, especially if the sun is out in the afternoon.
While natural activity has tapered we're still seeing results on the deeper layers of the snow pack. Mt. Norquay ski hill reported a size 3 cornice failure within the last 24 being the most recent.
Likely triggers for natural avalanches are cornice failures and solar radiation and possibly both.
Steep solar slopes at treeline and below are seeing the effects of the sun, with a significant sun crust in places. The various Jan PWL interfaces of sun crusts, facets, and surface hoar are now down 50-90 cm. The weaker Nov. 16 basal facet layer is down 50-120 cm and produces moderate to hard sudden collapse results in tests.
On Friday we should see the arrival of some snow, with flurries starting in the early afternoon. Southerly regions in the Park could see more snowfall with forecast amounts up 5 cm. Winds will pick up with strong gusts and temperatures will stay cold. An alpine high of -8 is being forecast.
Skies should clear Saturday, with light NW winds and only slightly warmer temperatures.
For a more detailed weather forecast, click here.
