Summary
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain
Weather Forecast
Tuesday: Light to moderate snowfall continues. Moderate south-westerly winds. Freezing level around 500m.Wednesday: The next storm pulse arrives with moderate to heavy snow. Freezing level rising to 1000m. Strong south to south-westerly winds.Thursday: Heavy snow. Freezing level rising to 1500m. Strong south-westerly winds.
Avalanche Summary
A few cornice-triggered and small skier-triggered slabs in the size 1-2 range have been reported since it began snowing on Friday. Earlier in the week, warming prompted a widespread natural cycle in the Coquihalla and skiers triggered very touchy persistent slabs at low elevations. An unnervingly large natural avalanche cycle occurred last weekend, with slabs up to size 4.5 propagating 2-3km along ridgelines and stepping down to the mid-February layer. Similar avalanches are possible as storm loading continues this week.
Snowpack Summary
Strong winds and new snow are expected to create wind slabs and storm slabs which are likely to fail in steep terrain, and could overload persistent weak layers. Persistent weak layers are variable in distribution across the region. A hollow series of poorly-bonded crusts was reported on southerly aspects in the Duffey Lake and Chilcotin regions last week, which may have healed somewhat with dramatic warming at the end of last week. A lower weakness comprising surface hoar, facets and a crust, has produced whumpfs and sudden planar ("pops") results in snowpack tests. It is still is a key concern for step-down avalanches in many parts of the region. It is especially prevalent on south-facing slopes above treeline, and all slopes below treeline.
pgoddard,
Avalanche Canada
