Southern San Juan
SnowpackChris Bilbrey · Feb 3, 2022 · Southern San Juan
Weather
Cold. Air temperature warmed from sub-zero in the morning to single digits by the afternoon. Winds were light out of the north and the sun made all the difference. No visible snow plumes off peaks.
Snowpack
New snow depths range from 5 to 7 inches between 10,000 and 12,000 feet. On southerly-facing slopes at all elevations, the new snow is settling quick and bonding fairly well to the firm crust below. Near and below treeline, the new snow lacks enough volume and is low-density limiting cohesive slab formation. We found decent bonding between the new snow and a 15 to 20 cm thick layer of near-surface facets on northwest-facing slopes. Only minor sluffing noted from ski pressure on steep, convex rolls - sluffs did not travel far. We saw very little evidence of recent wind-drifting along ridgelines and on open alpine slopes, but several soft slab avalanches ran mid-storm on north to east through southeast aspects. A snowpit on an east-facing slope at treeline confirmed a degrading upper snowpack and developing facets below a crust. Melt-water, driven by above freezing temperatures over the last month, has traveled around a foot below the snow surface. We spotted several frozen percolation columns that terminate and pooled above the pencil hard mid-pack slab. We did not observe concerning failures in facets below the crust, but this weakening structure will not support a big load and may be a wet snow problem if we see several days of non-freezing temperatures. No cracking or collapsing.