Yuba Pass Observations

We toured in the Yuba Pass area this morning. New snowfall amounts in the area from Friday night/Saturday morning were 2 inches of new snow. We saw evidence of previous drifting of this new snow by the NE winds that blew yesterday afternoon and last night.

We saw the debris and a 4 inch crown from a size D1 natural avalanche on a near treeline NW aspect (noted lat/long) that appeared to have occurred yesterday, Feb 11. We saw other areas of recent wind load that did not extend more than a few feet downslope on NW to W aspect near treeline terrain. Ski cutting test slopes produced very limited results.

The surface snow in sun exposed areas had become wet on S aspect terrain by midday. Snow in the shade on S aspect terrain had yet to enter melt phase.

We stopped and performed a couple of snowpit tests in an area where we knew that the Jan 29 surface hoar layer was 25-30 mm crystal size and buried about 1.5 feet below the snow surface. This is a spot where we have studied this layer several times over the past week. It is N aspect at 6,800' in below treeline terrain. We identified a portion of the slope we had not collapsed on previous visits to use for our tests. Our tests scored ECTP-16 and PST 25/100 end on the Jan 29 SH layer. While the layer remains reactive in this location, it is a very isolated snowpack presentation. The large grain SH at this location is becoming less upright with the passage of time. In the vast majority of the forecast area this layer is much smaller at sub 10 mm in crystal size and is not reactive.