Northern San Juan
AvalancheAmy Pertuz · Jan 3, 2020 · Northern San Juan
Weather
Mostly clear skies during mid day with some lingering orographic scuzz and increasing sky cover in afternoon. Crisp and beautiful day to get up high. Winds from the North were pluming off the tops of peaks, but winds were not adverse at treeline, and were not moving snow in a widespread way. Evidence of NW’ly winds with wind ripples and smooth pillows evident in some alpine slopes, while other slopes appear more undisturbed. Wind appears to have been concurrent with the snowfall, not after.
Snowpack
10” of new snow, low density. Some evidence of a mid-storm weakness (graupel?) with some small shallow storm slabs that were running within the new snow seen, and numerous dry loose slides in the expected places. No issues with bonding to the old surface were seen on Northerly aspects over 30 degrees. Snowpack is deep for this time of year...
Avalanche
No widespread avalanche cycle seen from this holiday storm, and no new slabs observed on North/ Northeast aspects. A handful of slab avalanches seen on aspects with suspected crust facet problems (SE, S) Deepest new slab avalanche observed was seen on Spirit Mountain, SE aspect, ATL, in a steep feature near the ridgline, broke below the new/old interface, and was small due to confined terrain feature, but a deeper slab than just the storm snow, HS-N-R1-D2-o. A storm slab in a steep rocky convexity was seen in mineral basin on an E aspect NTL, SS-N-R1-D2-i. Another slab was seen in the gut of the Hollywood slide path on Red3, a storm slab from earlier in the storm of week, NW aspect ATL, SS-N-R1D2. We stuck to N/NW aspects NTL, stayed on slopes below 40 degrees, great skiing with no signs of instability.