Southern San Juan
AvalancheChris Bilbrey · Nov 22, 2019 · Southern San Juan
Weather
Light snow showers that didn't amount to noticeable accumulation. Winds were light out of the northwest. Cool temperatures made it feel more like winter than late fall.
Snowpack
The snowpack around Coal Bank pass is the tale of two stories. Slopes facing east to south through west melted to bare ground before our recent storm. Storm snow accumulated right-side up and we observed good bonding between storm layers. Slopes facing northwest to north through northeast held marginal snow cover through early-November. Although depth and distribution of old snow varies within the San Juan Mountains, the common thread is that it's weak and cohesionless. Newly formed slabs are stressing this weak snow and signs of instability such as cracking and collapsing are noticeable once you approach treeline - some shooting cracks propagated outward around 100 feet from our skis. Extended Column Test also produced propagated test results with isolation and easy force. This problematic snow structure will most likely take some time to heal but defaulting to southerly-facing terrain offers generally safer conditions. Slopes below treeline that face north and northeast in this area have a similar structure as higher elevations, but a shallower weak layer and thinner slab was found in multiple locations. The snowpack does not appear to have reached its tipping point as you travel further below treeline.
Avalanche
None observed