Northern San Juan
AvalancheJeff Davis · Jan 8, 2017 · Northern San Juan
Weather
Warm, Wet, and Windy.
Snowpack
Warm temps continue to settle recent storm snow. Winds were strong enough to move snow on exposed slopes. Large cornices and pockets of wind-loaded snow were observed at all elevations. Little slab was observed in snow below treeline, but the avalanche I was investigating during this field day shows us how areas below treeline will become dangerous as weight is loaded. No sluffing was observed in pocket of wind loaded snow near treeline on ski cut. No cracking or collapsing observed throughout the duration of the tour.
Avalanche
SS-NC-R3-D2.5-G on East-aspect below treeline. Very impressive avalanche in Nevada Basin in an area called Nirvana. It looks as if this avalanche was triggered by cornice fall than gouged into a weak snow structure on the slope below. The crown ranged from 6" inches to 3' feet and was approximately 200 feet wide and ran 1200 feet though old growth timber. No trees were observed in the debris.