Avalanche Forecast

Friday night: Partly cloudy, light to moderate northwest ridgetop wind, freezing level 500 m.

Saturday: Mix of sun and cloud, light northwest to southwest wind, freezing level 900 m with a weak above freezing layer developing around 2000 m in the south.

Sunday: Mix of sun and cloud, moderate to strong northwest wind, freezing level 1200 m.

Monday: Sunny, moderate northwest wind, freezing level 1200 m.

Explosive control work on Friday produced wind slab avalanches up to size 2. A widespread natural avalanche cycle size 2-3 occurred throughout the region on Wednesday. Avalanche character was predominantly storm slab in the snowy north of the region and wet loose or glide slab in the rainy south. Northwest of Pemberton, several stepped down to buried weak layers resulting in very large (size 3-4) persistent slab avalanches.

• In the south of the region, fluctuating freezing levels during the last storm have resulted in a crust to ridgecrest. At upper elevations, 5-10 cm of dry snow has been blown around by the wind, exposing the crust in some areas and building wind slabs ontop of it in others. This MIN report from Nak Peak on Thursday depicts snow conditions changing with elevation.

• In the north, variable wind effect in the alpine includes scoured windward aspects, sastrugi, hard slab, wind pressed surfaces over lower density snow and isolated pockets of soft snow in sheltered areas above 2000 m. Wind slabs may remain sensitive where they overlie a spotty layer of surface hoar in sheltered terrain or a crust on solar aspects. A widespread surface crust exists below 1900 m.
• A melt-freeze crust from early December is found around 200 cm deep in the snowpack. This crust may have sugary faceted grains sitting above it. This persistent weak layer is most prevalent in the North (e.g., Duffey Lake, Hurley) and large avalanches have failed on this interface recently. This interface doesn’t seem to be a concern in the South (Coquihalla) and little information is known for the North Cascades or far South in Manning Park.

• Be careful as you transition into wind affected terrain.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Be aware of the potential for large avalanches due to the presence of buried weak layers.
• When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.