Observation: White Pine

Started my tour around 0930 from White Pine under overcast skies and temps around 30°. The front of the storm seemed to roll in around 1130 as the winds began to pick up and by 1230 winds were moderate, gusting strong at times, generally from the south.

I dug a pit in the Rock and Roll runout zone, in a spot I know is favored for snow and has not avalanched. Total depth was 255cm and the pit showed modest rounding in the PWL from November. I think we will begin to see more rounding and bridging in this layer over the next few weeks as it is buried under ~100cm of snow. I would caution extrapolating this data to other areas of the Cottonwood Canyons as this is a favored zone that is deeper than many areas. It also appears that the windstorm that follow our November drought period destroyed the surface hoar that was 155cm above ground and left dirt in this layer. I would doubt the same is true in sheltered terrain where this layer is likely present and possibly active. at 175cm above ground there is a notable weak layer from graupel that came at the beginning of one of the December storms. It may be that there was some graupel pooling in this spot. We haven't seen any failures on this layer but it was the weakest and most identifyable layer in this pit.

The story of the next few weeks will be what happens with the PWL. In favored areas, it is likely to continue to round and bridge but in areas with less snow (lower elevation, extreme terrain, paths that have already slid) I would hesitate to think that rounding is also occuring. The PWL will continue to be a problem requiring careful evaluation for the next couple weeks.