Avalanche Forecast

Good

Unsettled, stormy weather conditions continue through the forecast period. Overnight Wednesday: Snow amounts 5-15 cm. Ridgetop winds strong from the SW. Alpine temperatures near -6. Thursday: Snow amounts 15-25 cm. Ridegtop winds strong from the SW. Freezing levels 1300 m. Friday: Light-moderate snow amounts. Strong SW winds. Freezing levels falling to 600m. Saturday: Flurries. Possible sunny breaks, and freezing levels falling to valley bottom.

On Tuesday reports of natural sluffing from steep terrain up to size 1.5. On Monday, natural avalanches to size 2.5 were reported, some possibly triggered by cornice fall. Last 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 at the start of this month, with slabs up to size 4.5 propagating 2-3km along ridgelines and stepping down to the mid-February layer. Forecast heavy snow, and strong SW winds Thursday will elevate the danger ratings.

Strong winds and snow have created 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.