Avalanche Forecast

Saturday night: Increasing cloud, light to moderate southeast wind, freezing level valley bottom.

Sunday: Flurries, trace, moderate southeast wind, alpine high -8, freezing level 700 m.

Monday: Flurries, 5-10 cm, moderate southwest wind, alpine high -6, freezing level 1200 m.

Tuesday: Snow, 10-20 cm, strong southwest wind, alpine high -6, freezing level 1200 m.

We have received few reports of avalanche activity in the region since the mid-week storm slab avalanche cycle produced natural avalanches size 2-3.5. But with similar snowpack structure and recent weather patterns to neighboring Glacier National Park and South Columbia regions, we suspect that recent avalanche activity has been similar, but has gone unreported due to less backcountry traffic. 

Natural storm slab avalanches size 1.5-2.5 have been reported in GNP as recently as Friday. Notable avalanches in South Columbia include several skier triggered incidents around size 2 in the RMR slackcountry and a few natural persistent slab avalanches size 2.5-3 on northerly aspects in the alpine running on the early December persistent weak layer. See South Columbia avalanche summary for details.

Variably wind affected surfaces can be found at upper elevations. Around 50-80 cm of recent snow sits on a weak layer of surface hoar that was buried around Christmas at and below treeline.

A couple of persistent weak layers buried in early/mid-December are buried 90-150 cm down. Generally, they can be found as a layer of surface hoar above in close proximity to a crust/surface hoar layer. The form and distribution of these layers are highly variable and conditions may differ significantly from one valley to the next. 

• Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
• Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.