Northern San Juan
AvalancheJeff Davis · Jan 21, 2018 · Northern San Juan
Weather
Very cold blustery winter day. Snow continued to fall throughout the tour.
Snowpack
3 significant layers observed. 1- Old snow which is rotten. Facets and Depth hoar are large and well developed. But size of the layer varies from slope to slope and with elevation. N-E have the largest layers of old snow and weak-layers are the most developed. 2nd- 1/10-1/11 storm snow. This layers was becoming less reactive during last week’s temperatures swings and was also affected by the wind. 3rd-10"-30" of New and wind-drifted snow. Bad snowpack structure and step-down avalanches a real possibility especially near-treeline and below treeline on steep slopes that have the deepest old snow on the ground. Above treeline thinking most of the issues will be in the new snow as old slabs are dense, but if triggered avalanche will be large and dangerous. Compression test and extended column test show light to moderate failures on weak-layers near the ground.
Avalanche
Few small avalanche reported to me on the skin track by another group of skiers.