Avalanche Forecast

Moderate - We are confident about the possible sizes of avalanches, should one release; what is less certain is the likelihood of triggering.

Friday Night: Mostly cloudy, 0-5 cm of snow expected. Light variable winds, moderate southwest at higher elevations. Freezing level at valley bottom, alpine low around -13 C.

Saturday: Mostly cloudy, possible breaks in cloud in the afternoon. 10-20 cm of low density snow expected, with the higher amounts being expected in the south end of the region. Light to moderate east winds, trending to strong south at higher elevations. Alpine temperatures dropping to -15 C by late afternoon. 

Sunday: Partly cloudy. 2-5 cm of snow expected overnight, and 0-2 cm through the day. Light to moderate northeast winds, trending to southeast at higher elevations. Alpine temperatures below -20 C.

Monday: Sunny in the morning, mostly cloudy by the afternoon. No new snow expected. Light west winds, trending to strong northwest at higher elevations. Alpine temperatures around -17 C, with a possible temperature inversion meaning it could be even colder in the valleys. 

On Friday, a skier triggered size 2.5 persistent slab avalanche was reported in the backcountry near Blackcomb. It was around 110 cm deep, in a northwest facing feature around 2100 m. Last week's forecaster blog is still relevant.

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.

10-15 cm of low density snow overlies 30-70 cm of snow that fell Tuesday and Wednesday with generally strong southerly winds. Expect the wind transported snow to be deeper and more reactive on leeward slopes.

The storm snow sits on a variety of old 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 (mostly reported in the southwest of the region. 

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.
• Start with simple terrain and gather information before thinking about more committing features.
• Give the new snow time to settle and stabilize before pushing into bigger terrain.
• Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.
• Avalanche hazard may have improved, but be mindful that deep instabilities are still present.