Regions
Banff Yoho Kootenay.
Weather Forecast
For tonight and Saturday, expect rain to continue to 1800 m and snow above that. Winds to remain moderate to strong. Late Saturday, the winds will shift to a northerly direction in advance of a cold front that could deliver another 10-15 cm to upslope regions. Temperatures will drop through Sunday and the precipitation will end.
Snowpack Summary
Some rain below 1800m Fri afternoon, and 10-20cm snow over last 24 hrs. building soft slabs in alpine areas. Rapid settlement due to warmer temps. New snow sits over previous wind slabs to 25cm thick with stubborn hard slabs below. W of the divide the mid-pack is generally well settled. E of divide the mid-pack is faceted and weak.
Avalanche Summary
A skier accidental with no burial size 2.5 occurred on a steep cross loaded feature in the National Geographics, near Lake Louise Thursday. The hard slab was 40-60 cm thick and ran the full length of the path. Sunshine and Lake Louise ski hills reporting only sz.1 ski cuts and naturals out of steep ridgetop terrain, reloading through the day.
Confidence
Intensity of incoming weather systems is uncertain
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.