Cayoosh

Widespread evidence of a natural avalanche cycle in the Cayoosh valley. Numerous southwest to southeast slopes between Cayoosh and Marriot slid to size 3. Several of these slides ran full track, including one that appeared to slide to ground. At roughly 11:30, we heard a very loud noise coming from the Rohr Ridge area. We think this may have been a large cornice fall, but did not see the event. Not all alpine slopes went in this most recent natural cycle - we chose to avoid slopes with overhead hazard due to our uncertainty around cornices and the Dec 9 persistent weak layer.

Most of the day was overcast with temperatures near zero degrees. On our ski out (15:00) it was snowing s-1.

Did a quick test profile in the upper snowpack. CTM 12 (SP) x 2, down 10 on Melt-freeze crust. A thin melt-freeze crust surrounded by variable grain types (some facets, some surface hoar) was roughly 10 cm's below the surface. About 50 cm's down is a later of surface hoar. Only test results observed were on the upper crust layer. We did not test the December 9 crust / facet layer.