Avalanche Forecast

Thursday night: Increasing cloud, moderate to strong southwest wind, freezing level 600 m.

Friday: 5-10 cm new snow, wind easing moderate to light southwest, alpine temperature -4 C, freezing level 900 m.

Saturday: 5-10 cm new snow, wind increasing to strong southwest, alpine temperature -5 C, freezing level 900 m.

Sunday: Clearing, light to moderate southwest wind, alpine temperature -2 C, freezing level 1500 m.

Numerous wind slab avalanches were reported Tuesday, triggered naturally and by riders at treeline and alpine elevations. Most occurred on wind loaded southerly aspects due to recent northerly wind. Check out these MINs for a few examples: here, here, and here.

A few large avalanches have been observed on the weak layers described in the snowpack summary within the past week and they were triggered triggered by riders, explosives, and naturally. They occurred on northerly aspects between 1900 and 2100 m and were generally 30 to 50 cm deep.

5-10 cm of new snow is forecast to fall through the day Friday. The new snow falls over hard wind slabs and wind scoured surfaces in exposed terrain, and a melt-freeze crust on solar aspects at upper elevations.

Two potential concerning weak layers may be present in the snowpack: 

• The shallower layer, around 50 to 80 cm deep, includes feathery surface hoar crystals. This layer may be found in sheltered terrain features at treeline and lower alpine elevations but has been reported as spotty across the region. 
• The more widespread weak layer includes sugary faceted grains that overlies a hard melt-freeze crust. This layer ranges in depth from 10 cm to 100 cm due to the wind scouring and loading the snow in different terrain features over the past two weeks. The layer has been reported as being widespread up to around 2000 to 2200 m. 

To date we have mostly seen sporadic avalanche activity on these layers, but they remain possible to trigger where they exist in the mountains.

The remainder of the snowpack is well-settled.

• Recent new snow may be hiding windslabs that were easily visible before the snow fell.
• Be careful as you transition into wind affected terrain.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.