Northern San Juan
SnowpackAmy Pertuz · Jan 15, 2023 · Northern San Juan
Weather
Warmish temperatures in the upper 20s this morning, with snowfall ramping over the morning from S-1 to S2 by late morning. Winds out of the south ramped up as well, moving snow and creating soft drifts on lee northerly features and open areas below tree line. 4.5 inches of new snow at pass level by mid day. Snowfall intensity and totals dropped off around Ironton at 9800 feet, but precipitation was falling as snow all the way to low valley bottoms.
Snowpack
The 4” of new snow this morning at pass level was falling warm and was fairly dense (10% water content) and was bonding well to the northerly and easterly below tree line slopes I traveled on. Steady SSW winds were moving snow at all elevations, creating soft drifts in open areas below tree line, and generally drifting northerly slopes. The snowpack here is just shy of 2 meters deep, and has showed signs of stabilizing since the big storms over the holidays. The primary persistent weak layer of concern was found 125cm below the surface on the below tree line northeast slopes I traveled on. I was able to initiate propagating failures in this layer with 27 taps. This is a deep layer to be able to initiate such a failure still, and these results point to the low-probability/high-consequence nature of the avalanche risk in this type of Moderate rating: It takes a lot of force or requires you to find just the right thin spot on a slope where you can impact the persistent weak layer, but a deep and dangerous avalanche results if you do. That will continue to steer my terrain choices towards the conservative end of the spectrum for a while longer.