Avalanche Forecast

Thursday Night: cloud cover breaking overnight. 0-5 cm of snow expected. light to moderate southwest winds. Freezing level at valley bottom. Alpine low around -13 C.

Friday: Partly cloudy, possible trace of snow expected, overcast and up to 10cm expected closer to squamish and the south coast region. Light northeast winds. Freezing level at valley bottom, alpine high around -11 C.

Saturday: Mostly cloudy. 2-6 cm of snow expected overnight, with another 5-10 through the day. Moderate northeast winds, trending to strong south at higher elevations. Alpine temperatures dropping to -15 C by the evening. 

Sunday: Partly cloudy. 2-5 cm of snow expected overnight, and a possible trace through the day. Light to moderate northeast winds, trending to southeast at higher elevations. Alpine temperatures below -20 C.

On Thursday, avalanche control with explosives triggered many size 2 avalanches in the storm snow. A couple of size 1 skier triggered avalanches were also reported in steep, unsupported terrain.

Other professional operations reported evidence of a natural avalanche cycle earlier in the storm, and a few recent size 2 natural avalanches in the storm snow, in north aspects, just below ridge tops.

On Wednesday, avalanche control with explosives triggered size 1.5 to 2 avalanches in the storm snow. Northwest of Pemberton, the storm slab was reported to be touchy, with a natural avalanche cycle up to size 2.5 overnight.

On Tuesday, a few wind slab avalanches triggered by skiers were reported in the Pemberton area. 

On Monday, a snowmobile triggered avalanche was reported near Appa Lake, sliding on the early December crust/facet combo. See Mountain Information Network post here.

Storm slab avalanches have the potential to step-down to recently reactive buried weak layers, with the potential to produce very large, destructive avalanches.

30-70 cm of storm snow fell Tuesday and Wednesday with generally strong southerly winds. Expect the new snow to be deeper and slabbier on leeward slopes.

All this new snow sits on a variety of snow surfaces: variable wind slabs and hard wind-scoured surfaces in terrain exposed to the wind, and preserved powder and possible surface hoar in sheltered areas. 

A weak layer of facets (sugary snow) can be found over a widespread crust that formed in early December (down 100-200 cm). This layer has been most reactive at lower alpine and treeline elevations, between 1500-2100 m. Large size 2 and 3 avalanches on this persistent slab problem have been reported recently. This problem is particularly hard to predict and tricky to manage. Get more details and photos in our forecaster blog. 

• Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
• Give the new snow time to settle and stabilize before pushing into bigger terrain.
• Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
• Keep in mind that human triggering potential persists as natural avalanching tapers off.