Northern San Juan

Snowpack

Bill Nalli · Jan 4, 2020 · Northern San Juan

Weather

Calm winds and high clouds in the morning gave way to clearing skies and an increase in solar input. SW wind picked up after 2pm with average mid 20's G30's. Lots of snow being transported above treeline onto NW-N-NE-E aspects.

Snowpack

Southeast aspects are still the bullseye for persistent slab instabilities but south and southwest slopes are also suspect. The crust/facet combinations that exist on these aspects near and above treeline are slow to heal. There is also great variability in snow depths in the alpine. The wind shifting from SW to N to SW over the last couple storms is complicating things and making it difficult to know where the snow has been blown. Areas with less than 120cm still harbor weak faceted snow near the ground. There was lots of natural activity on south facing aspects above Ophir at the end of the last storm when north winds deposited snow onto these aspects. Some of these slides failed at faceted layers mid-pack and some all the way to the ground. I experienced a couple collapses on an east aspect at 12,200' adjacent to the slide from two days ago in Spring Gulch that got my attention and ended my attempt to go further into more exposed terrain. A snow profile in this area revealed 90cm HS with 40 cm of 3-4mm depth hoar. Not much of a slab on top of it at the moment made for non-propagating results in extended column tests. Near and below treeline things are less complicated and stronger. Late in the day once the high clouds moved out and the sun was more intense the snow surface got wet below treeline and I was able to get some small wet-loose slides moving on slopes over 38 degrees.