Lizard-Flathead

Avalanche conditions are still very dangerous! It's hard to have any confidence traveling in the backcountry with such a complex snowpack and sustained warming.

-

TUESDAY: Increasing cloud throughout the day, moderate southwest winds, mild inversion with alpine temperatures hovering around 0 C.WEDNESDAY: Light flurries in the afternoon, strong southwest winds, alpine temperatures around - 2 C.THURSDAY: 5-10 cm of new snow, strong southwest winds, alpine temperatures around -5 C.

On Monday, a few solar triggered avalanches (up to size 2.5) were reported in steep terrain. A small wind slab (size 1.5) was also reported on a northeast alpine feature. On the weekend, explosive testing produced several large persistent slab avalanches on deep weak layers, including a size 3.5 persistent slab that failed on the November crust. This avalanche ran nearly 800 m and exceeded the path's historic runout distance. Very significant avalanche activity occurred in the region last week, and the potential for more large avalanches remains.

Warm alpine temperatures are rapidly settling recent storm snow as well as forming moist snow on solar aspects. More importantly, warming is stressing deeper layers in the snowpack. The early January surface hoar layer is roughly 60 cm below the surface and the unstable weak layer from mid-December (predominantly surface hoar and/or a sun crust) is found roughly 100 cm below the surface at treeline and below treeline elevations. Below, a rain crust that developed late-November with associated sugary facets is also being stressed. Snowpack test results show sudden fracture characters and high propagation potential for all of these buried layers, indicating that they can be triggered and could propagate into large, destructive avalanches.