Southern San Juan
SnowpackChris Bilbrey · Mar 21, 2023 · Southern San Juan
Weather
Wet, damp day. Moderate to heavy snowfall with generally light winds around 11,000 feet. About 3 inches of new snow accumulations between 10 AM and 3 PM.
Snowpack
We found around 30 cm of new snow in the valley bottom. This quickly increased to between 45 and 55 cm as we traveled higher in elevation up to about 11,300 feet. Initial snowfall (about 20 cm) arrived during the cold part of the storm. Later storm snow layers fell as the temperatures warmed creating an upside-down (inverted) storm slab. This made for tough travel conditions today. You could feel the storm snow collapse below each step and we noticed cracking along the skin track. The latest storm slab sits above a faceted snow surface on northerly-facing slopes, and above a firm crust on slopes facing east through south to west. Snowpack test on north and northwest-facing slopes failed with easy force in CTs at the interface of the obvious density change. ECTs propagated in multiple test at the same density change with 12 and 13 taps. We also observed non-propagating failures at the interface between the last two storms that could become more reactive with additional snow load. Numerous small loose snow avalanches on slopes that approached 35 degrees during a period of high PI today.