Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Glacier.
A touchy layer should have you tip-toeing around in the mountains. Be conservative in your terrain choices and diligent in group management; regroup is safe spots and be aware of who is above and below you.
Weather Forecast
The forecast is unsettled through Saturday. Mainly cloudy, with light flurries and moderate SW winds at ridgetop. While there won't be enough new snow to add significant load, there is lots of storm snow to be transported by the winds, and windslab development is expected.
Snowpack Summary
Cooling temps will tighten the 50-70cm deep storm slab, which sits on well preserved and widespread Dec 17th surface hoar layer (10-20mm). The surface hoar sits on top of a rain crust up to 2100m, and on well settled snow above 2100m. The Dec 9th surface hoar layer is down 80cm in the area. The Nov 9th crust is 30cm up from the ground.
Avalanche Summary
Avalanche control yesterday triggered 16 size 3 to 3.5 avalanches, including this one off the West face of Cougar Mountain, and over 20 size 2's. Wide propagations were observed. Recently skier triggered and skier remote triggering of the slab from over 50m away continue to occur. Most of the activity was occurring between 1700-2400m.
Confidence
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.