Persistent slab snow structure in southern Glacier

Today's FAC avalanche forecast listed Persistent Slab as the only avalanche problem. To evaluate this, we visited the eastern portion of our advisory area which is known for its weak snow.

• A surface rain crust exists from the trailhead at 4500' to 6100'.
• Above 6100', a dense storm slab (2-4") caps lower density snow creating an upside down snow surface.
• One large Persistent slab avalanche was observed in the North Fork of Dickey Creek. This likely ran during the 1/7 storm.
• Sunny conditions moistened the surface snow on steep sunny aspects below 6500'. No rollerball or wet loose activity was associated with today's warming in this area.
• Our snowpit @ 6900' had a Persistent slab snow structure. Stability tests revealed propagation with moderate force on the basal facets.