Northern San Juan

Avalanche

Chris Bilbrey · Apr 16, 2024 · Northern San Juan

Weather

Lots of sunshine with a few passing clouds midday. Moderate northwest winds in the morning decreased significantly by early-afternoon. Temperatures were noticeably warmer below treeline and in sheltered areas.

Snowpack

We found 6 to 8 inches of new snow above treeline and drifts in the 8 to 10 inch range. The new snow progression from below treeline through near treeline ranged 2 to 3 inches and 3 to 5 inches respectively. Strong winds before and during snowfall deposited deeper snow totals on northeast, east, and southeast aspects. We found about half the depth of new snow on south aspects. Southwest, west, and northwest aspects were mostly scoured by recent winds leaving the old snow surface exposed. North aspects were a mish-mash of drifted areas adjacent to wind-scoured areas. We found generally good bonding at the new-old snow interface, and the new snow was dense - mostly 1F and uniform. As today's sun warmed the snow surface, we started observing small rollerball dribblers in isolated spots - especially below exposed rocks and where the old dusty snow surface was visible. Above 13,000 feet, the snow surface remained mostly dry across sunny aspects. Once we descended lower in elevation in the afternoon, the new snow was quickly becoming wet, sticky, and losing cohesion. The lack of new snow volume at lower elevations significantly reduced the new, wet snow hazard - although we started to experience minor "trap-door" conditions below 11,000 feet.

Avalanche

We triggered one small, isolated pocket of drifted snow. This was located directly below the ridgeline on an easterly slope. It ran above the firm old snow surface for approx. 100 feet before coming to rest. Did not pose a hazard to the adjacent skier.