West ridge off Lone Tree, 7553', NE aspect, slope angle varied from 29 degrees to 36 degrees, 10" depth, 150' wide, approximately 500' length, 200' fall. SS-ASr-R2-D2-I. This avalanche was remotely triggered from about 40 feet away. The weak layer was 0.5 - 1 mm facets atop the rain crust from early March.
Signs of Unstable Snow
Did you see shooting cracks?
Did you experience collapsing or whumpfing?
PAC toured out of bounds from Tamarack Resort yesterday, Monday, March 14. I observed southern aspects that had 1-2" of new snow sitting atop a very slick crust from the rain event 03/01. There was a myriad of facet and crust combinations within the upper two to three feet of snow on solar aspects. Wind-deposited snow was evident on east through north-facing terrain. In protected, north-facing terrain, dry loose snow was moving easily on the surface. While touring up the west ridge of Lone Tree, I remotely triggered a small avalanche (see info and photos above) from about 40 feet away. Wind-deposited snow in this terrain was deeper, denser, and more reactive. The wind slab failed on facets sitting atop the rain crust. I skied an east/northeast ridgeline on the descent and noticed new snow becoming moist on the east aspect while staying softer on the northeast side of the ridge. A thin, breakable recrystallization crust was noted throughout the tour underneath the new snow and above the rain crust.
The weather was mild, winds were light out of the southwest. Skies remained overcast throughout the day with only a few brief moments of sun poking through the clouds. Temperatures were warm enough to impact new snow.
Observed Avalanche Problem #1:
Wind slab was observed on specific terrain features on the leeward side of ridgetops. Mainly confined to East, Northeast, and North-facing terrain. Size was small to large (D1-D2). Likelihood was possible, weak layer was 0.5-1.0 mm facets atop the 03/01 rain crust.
Observed Avalanche Problem #2:
Dry loose was isolated to steep, protected, north-facing terrain. Size was small (D1), likelihood was possible. This was a new snow problem.