North Bowl Obs

Our group traveled in the north bowl of Castle Peak today. Cold temperatures throughout the week and cloud cover yesterday seemed to have kept the surface snow fairly well preserved on the northerly half of the compass this morning.

Upon arriving at the top of the ridge we had a look down into the N facing gullies. The N and NW facing micro aspects of start zones had been scoured by the NNW winds on Thursday while the NE facing sidewalls had some isolated pockets of wind drifted snow. Northerly facing cornices looked modestly eroded as well. Days since the last wind event and an abundance of tracks in the region indicated that wind drifted snow had likely since bonded to the underlying snow surface.

We skied the N facing chute one at a time while entering from scoured portions of the start zone. New snow that was still relatively cold and soft from the last storm could be found in the more sheltered portions of the chute and I was thinking about the isolated potential for persistent grain instabilities. Probing with my ski pole in between turns I could feel a relatively stout layer underneath the recent snow and only with considerable effort could I push through into a more unconsolidated layer. Once tucked behind a rock outcrop mid-chute I isolated a mitt pit with my ski pole that revealed the new snow transitioning down to a thinner 1F-1F+ layer that was atop a more unconsolidated layer of facets. I was able to get the slab to release from the facets with moderate – hard force and a Q3 shear. While the structure was poor, the new snow still did not seem to have enough of a difference in hardness from the faceted layer to create concerns for potential propagation.

While traveling on sunnier ENE aspects we were able to get 2 – 4 inch pinwheels by rolling snowballs downhill around 11am. Poking around on these aspects revealed a similar structure as before but with more warming of the surface snow. While the surface snow was becoming considerably saturated, neither the crust nor the faceted layer underneath seemed to be and ski cuts / traverses did not produce any loose wet activity.