Northern San Juan
AvalancheJeremy Yanko · Mar 3, 2022 · Northern San Juan
Weather
Warm-Breezy, high thin cirrus cloud cover burning off around 11:30. Thicker mid-level band of clouds rolled in around 2.
Snowpack
Checked out current conditions from 10,000-12,300ft on predominantly north and west aspects. Below treeline: W/NW aspects developed a 1-2cm pencil hard crust over moist rounds below. Due north still holding cold-soft snow. Tried with diligence to get a collapse in the undisturbed flats and on short steep test slopes but to no avail. The ongoing cracking and collapsing found the previous 9 days has calmed for now in this drainage. Found off and on supportability of the upper slab where it would take 3 good kicks to push a ski through the 30-40cm dense slab into weakness below. Though boot penetration sample sites gave way to full leg depths into the foundationally weak snowpack. It is very easy and consistent to feel the buried near surface cavity (2/21 layer) via pole probing through the perched upper slab. Seems the Persistent problem is trending toward dormant but see it quickly re-activated with modest new snow totals. Near treeline, NW aspect sampled holds a 185cm HS with a 45cm settled 4F slab ontop of the 2/21 buried near surface facet layer, yielding mod-high snowpack test score. The dust layer near the new/old interface is not as distinct in the profile and looks somewhat diffused into the pack. Found one collapse Above treeline in a gully compression feature adjoining a W/NW aspect. Largely wind pressed surfaces w/ wind crusts and thin slabs on the W/NW faces but decomposing into textured near-surface facets. W/SW have a 2cm pencil Melt-feeze crust cap over moist rounds below. HS of 185cm on a West facing aspect at 12,200 giving way to fair/good stability at this location.
Avalanche
Two large avalanches estimated to have run around 2/23-25. Uncertain on trigger as helicopter blasting is active in this zone.