Northern San Juan
AvalancheKaylee Walden · Dec 8, 2022 · Northern San Juan
Weather
Approx. 9" of snow had accumulated from the storm cycle over 48 hours at above 10k on northerlies, and previous wind loading was obvious especially near ridgelines. Prevailing wind direction throughout the storm had been out of the W/SW with brief periods of wind from the E. Temps were cold, but warming throughout the morning (from 5 to approx. 20 degrees F throughout the day). Solar affect was not as strong due to lower sun angle. Extraordinarily calm, without a noticeable breeze even at ridgetop (~12k).
Snowpack
9" of low density snow fell atop variable snow surfaces depending on aspect/elevation: Westerlies have a stout mid-pack layer of 1F hard windpressed snow over facets, northerlies are weak and faceted to the ground, and lower elevations and more solar aspects had a noticeable temperature crust beneath the storm snow. Virtually all aspects aside from southerlies (W-NW-N-NE-E)showed us either signs of instability or evidence of natural avalanches.
Avalanche
Starting at 0800 we ascended a mining road out of the town of Ophir, traveling from Waterfall Canyon to Swamp Canyon. We began to break trail above a mining road on a west aspect at approximately 10,800'. The snowpack was touchy and very communicative: We heard many rumbling collapses and observed shooting cracks. We were sure to travel only on and beneath low angle slopes, and spaced out to avoid exposure to micro terrain features that appeared wind loaded. We had anticipated after observing previous cracking, collapsing and wind loading that the steeper north slopes off the ridge would be easy to trigger, and kept our distance accordingly. We remote triggered the avalanche from about 10' away, atop very low angle terrain on the ridgeline. No other parties were observed in the area.