Wind slabs can currently be found on almost any aspect. Expect those on steep southerly slopes to be especially touchy.
Confidence
High - The weather pattern is stable
Weather Forecast
Thursday: A mix of sun and cloud with no new snow. Winds light from the west. Alpine temperatures to -8.Friday: Cloudy with sunny periods and no new snow. Winds moderate to strong from the west. Alpine temperatures to -4.Saturday: Mainly cloudy with isolated flurries and a trace of new snow. Winds moderate to strong from the southwest. Freezing level rising to 800 metres with alpine temperatures to -3
Avalanche Summary
A MIN report from Tuesday details a skier triggered avalanche involvement in the adjacent South Coast Inland region. The avalanche was triggered in a rocky section of a steeper southeast-facing slope where there appeared to be evidence of recent wind loading. Tuesday's wind event resulted in numerous Size 1 wind slabs running naturally on steep southerly slopes. Natural avalanche activity was focused in areas that had more new snow available for transport by our outflow winds. Crown depths ranged from 15 cm up to 40 cm in heavier snow areas. Previous to this activity, observations on Monday revealed widespread soft slab activity (to Size 1.5) on northerly aspects with explosives and skier traffic.
Snowpack Summary
New snow from Sunday-Monday totalled 18 cm near Whistler while 25-35 cm fell in the upper Callaghan / Powder Mountain area. In the days since the storm, winds shifted to classic outflow (northerly) patterns with strong winds at ridge top. This resulted the new snow being 'reverse loaded' onto southerly slopes as wind slabs and soft slabs. These slabs are the primary weaknesses of concern in the snowpack and our colder-than-usual temperatures mean the upper snowpack will be slower than usual to heal. Deeper in the snowpack, the new snow from Sunday night and also last Friday is bonding fairly well to a variable surface consisting of a mix of soft wind slabs, hard wind slabs, sastrugi, faceted snow, and even some surface hoar. Snowpack layers below this interface are generally well bonded, and the lower snowpack is solid.
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.