Avalanche Forecast

Monday night: Flurries, up to 5 cm, moderate to strong southwest wind, freezing level 500 m.

Tuesday: Scattered flurries, moderate to strong southwest wind, alpine high -5, freezing level 1300 m.

Wednesday: Snow overnight then clearing, 5-15 cm, southwest wind easing to light, alpine high -5, freezing level 1300 m.

Thursday: Sun and cloud, light southwest wind, alpine high -3, freezing level 800 m.

Over the weekend, a large natural storm slab avalanche cycle was observed up to size 3 in much of the region and up to size 4 near Pemberton.

Persistent slab avalanche activity has tapered significantly since the cycle early last week, but persistent slabs size 2-2.5 were still triggerable by explosives on weekend. Events from last week include:

• A fatal avalanche in the South Coast Inland region (near the Sea to Sky boundary) north of Pemberton in the Railroad Pass area last Monday. It was reported to be a size 2 persistent slab avalanche on a west aspect, around 1650 m. The RCMP press release can be viewed here, and the Avalanche Canada report can be found here.  
• A size 2 avalanche was triggered on Monday by a skier on a northwest aspect in the alpine on Mt. Matier (Duffey). The avalanche occurred on a northwest aspect and was likely a wind slab avalanche. It carried the skier over cliffs resulting in several injuries. A MIN report detailing this incident can be found here. 

These avalanches highlight the ongoing potential to trigger persistent weak layers in the snowpack. 

Over 70 cm of recent snow has seen extensive wind affect at upper elevations, with scoured windward aspects, wind slabs in lee features and growing cornices at ridgetop. In sheltered areas below treeline, recent snow may be sitting on surface hoar. 

A melt-freeze crust from early December is found around 80 to 180 cm deep in the snowpack. This crust may have surface hoar or sugary faceted grains sitting above it. This persistent weak layer is most prevalent in the north (e.g., Duffey Lake, Hurley) and found to a lesser extent in the south of the region.

The remainder of the snowpack is generally well settled.

• Start with conservative lines and watch for clues of instability.
• Be careful as you transition into wind affected terrain.
• Avalanche hazard may have improved, but be mindful that deep instabilities are still present.