Northern San Juan
AvalancheAmy Pertuz · Dec 17, 2022 · Northern San Juan
Weather
Clear skies and milder temperatures today, with highs in the teens in the canyon creek gorge. Moderate west-northwest winds at ridgetop were spinning small ribbons of snow off high ridgetops, but I didn’t see any noteworthy blowing snow.
Snowpack
The snowpack in the area surrounding Camp Bird Road is similar to that of Red Mountain Pass in overall coverage. Height of snow on below tree line SE aspects traveled on ranged from 50 to 70cm. On a SE aspect at 10,600ft the snow depth was 78cm. Large grained facets making up the bottom 20 cm at the ground had ragged failures in CT and did not propagate in ECTs. At 32cm, a facet-crust combo was the primary layer of interest and had hard resistant planar failures in CT (22) but did propagate in an ECT (ECTP) on 24 taps. This was likely the layer responsible for the whumphing on this aspect. Not the kind of large, rumbling collapses you can experience right now on below tree line northerlies, but sometimes tens of meters. Snow coverage in still building on this aspect, and near and above tree line slopes looked very thin. Supportability was fairly consistent on skis. Surface hoar to 3mm was widespread between 10, 200ft and 10, 600ft. Evidence of wind loading from northerly winds mid week was visible as smooth pillows in cross loaded gullies.
Avalanche
No recent slab avalanches visible with good viewing conditions today. One old slab SS-N-R2-D2-N on a Westerly aspect NTL in Fall creek was estimated to have run 12/8. The beginning of a loose dry cycle is happening in this area on northerly and westerly aspects with cold temperatures and cohesionless snow common on the surface