Avalanche Forecast

Moderate -

Thursday night: Flurries bringing 5-10 cm of new snow. Moderate to strong southwest winds, gusting to extreme in the south of the region. Friday: Continuing flurries bringing 5-10 cm of new snow to the south of the region. A trace of new snow in the north. Moderate to strong southwest winds, gusting to extreme in the south of the region. Freezing level to about 1500 metres with alpine temperatures of around -2. Saturday: Flurries bringing 5-10 cm of new snow. Moderate to strong southwest winds. Freezing level to 1600 metres with alpine temperatures around 0 in the south of the region, closer to 1300 metres and -4 in the north. Sunday: Cloudy with scattered flurries bringing up to 5 cm of new snow, mainly in the south of the region. Moderate to strong southwest winds. Freezing level to 1600 metres and alpine temperatures around -1.

Reports from Wednesday include observations of several 24-36 hour old natural storm and wind slab avalanches that had released from Size 1.5-2.5 on southeast to southwest aspects at treeline and above in the north of the region. Crown fractures averaged 40-70 cm but reached as deep as 120 cm. On Tuesday morning, solar trigger sluffing was reported in the Coquihalla. In the north of the region, the top 10-20 cm was reported to be sluffing easily in steep terrain. On Monday, explosives triggered three size 2.5 slab avalanches in the Duffey area which released on late-February sun crust down 40-50 cm. These were on southeast through southwest aspects at 2000-2200 m elevation. Extensive whumphing was also reported in the north of the region on Monday.Looking forward, large persistent slab avalanches remain a concern for the accumulated snow from the past week releasing on the February weak layers. It may still be possible for a person to directly trigger a persistent slab or a smaller avalanche could step down. Recent strong southwest winds have also created new wind slabs in immediately leeward terrain features which are expected to remain reactive on Friday.

Another 10-25 cm of new snow from Wednesday brings the typical storm accumulation in the past week to 55-80 cm in the north of the region and to well over a metre in the south of the region. Strong south and southwest wind during the storm redistributed much of this snow in wind-exposed terrain, forming thick wind slabs. The new snow overlies the mid-February and late-February interfaces which may be close together in the snowpack. The late-February interface consists of wind affected surfaces in exposed terrain, sun crust on steep solar aspects, and facets and surface hoar in sheltered areas. The mid-February interface consists of a thick rain crust which extends to at least treeline, a sun crust on steep solar aspects, and in many places, a layer of facets overlying the crust. Recent observations suggest the late-February layer is most reactive in the north of region and the mid-February layer is most reactive in the south of the region. Below these layers, the mid and lower snowpack are generally well settled and strong.