Teanaway Drainage

It was a lovely day in the mountains with around 4 inches of new snow over a supportable crust. I even enjoyed some clear skies between cloud layers in the early afternoon. The fresh snow buried a few notable weak layers. However, that new snow lacked a cohesive slab structure, and other than isolated cracking on a couple of kick turns, I saw little signs of instability. There was a notable lack of wind drifting. Even along ridgelines above 6000ft, there were no signs of wind slab development or drifting during the storm. Afternoon warming and sun breaks led to a few rouge rollerballs, but they lacked energy and were not widely distributed. 

In the valley bottom, there was around 3cm of new snow. New snow depths increased to 10cm by 4500ft and 15cm by 5800ft. The fresh snow buried a breakable melt-freeze crust with approximately 1cm of weak faceted grains and surface hoar. This crust was more robust at lower elevations and southerly aspects, but it was barely discernable on a west aspect above 5500ft. While the new snow lacked enough cohesion to form a slab, informal snowpack tests showed signs of reactivity at this new interface (1/2 SH). Hand shears released easily on the surface hoar layer just above the crust, and tilt tests produced clean shears on the thin zipper crust just below the faceted grains and surface hoar. Compression tests also showed sudden results on these layers (CT7, SP,↓13) / (CT9, SP, ↓15), although extended column tests and propagation saw tests did not indicate a propensity for propagation yet. 

I found a snow height of 112 cm in a snow profile at 5800ft on a west aspect. The snow surface was precipitation particles over the weak snow layers and thin crust described above. The mid-pack consists of refrozen melt forms, and rounding faceted grains. The early December melt-freeze crust is buried 60cm deep and hard enough to be challenging to shovel through.