Northern San Juan
AvalancheBill Nalli Jeff Davis · Dec 1, 2019 · Northern San Juan
Weather
Clear skies in AM with high thin clouds moving in by afternoon. Calm winds and mild air temps.
Snowpack
The snow surface became stiffer as we gained elevation. Many leeward slopes were heavily wind-loaded during this past winter storm. Cracking was observed in wind-loaded areas that went to the ground and pulled into the flatter terrain above. It is unknown if these cracks were from today or yesterday, but looked to be triggered by humans traveling on the nearby skin track. We felt one significant collapse while traveling on the skin track as well. Digging on an east aspect at 11,700' the layer of facets near the ground was not as developed as in other areas in the North San Juan zone and we did not get propagating failures on long column tests. We believe this area did not have much snow prior to the winter storms at the end of November. With ample sunshine and warming temperatures rollerballs and small point releases were observed on sunny slopes in the afternoon.
Avalanche
Natural avalanche activity was observed on North and East aspects above treeline. The avalanches were shallow, but ran long distances. New and Wind-loaded snow has likely covered more evidence of the natural cycle.