Buried Surface Hoar and Small Wind Slabs on Mt. Rose

Upon arriving at the trailhead, we found about 2-3 cm (1 inch) of new snow on the ground. In the first open meadow at 7560', we found buried surface hoar underneath the 2-3 cm of new snow. As we ascended up to ~10,000', we kept checking for it at regular intervals and were able to identify buried surface hoar 2 to 5 cm's below the snow surface all the way up to the exposed ridge on the shoulder of Mt. Rose. It was most prominent on sheltered shaded slopes facing N-NE-E. When we got to the ridge we also found some small wind slabs had formed. Some of these were very sensitive and easily failed and others did not. We were not able to identify the weak layer in the ones that failed due to moderate blowing and falling snow, but it seemed like the ones that failed did have some signs of buried surface hoar being the weak layer. None of these test slope failures were very large and did not involve enough to snow to cause problems at that time, but with additional snow and wind, they could get bigger quickly as the storm continues. By the time we got back to the car @ 1:30 pm, another 2-3 cm of snow had accumulated. Driving back to Truckee snowfall became more intense and by the time we got back to the office @ 2:30 pm there were 15cm (6 inches) of new snow in the parking lot. 

Photo 1: Surface hoar buried under ~2-3 cm (~1 inch) of new snow.

Photo 2: Small failure on a wind-loaded test slope that we think failed on the buried surface hoar.