Southern San Juan
SnowpackChris Bilbrey · Dec 17, 2021 · Southern San Juan
Weather
Cool, sunny day with light winds along ridgelines. Winds did their damage already, and no snow blowing in the alpine - many southwest ridge tops are scoured down to bare ground.
Snowpack
We targeted east-facing slopes to investigate sensitivity of faceted crust and NSF(s) below our recent storm snow. We identified two interfaces within the top 50 cm's near treeline. These layers produced sudden planar failures in Compression Test but were stubborn - took hard force to initiate failure. Crust around the facets where we dug today was thinner and not as firm as other locations in the South San Juan where we found this structure. Above treeline, concerning facets rest under a stout meter thick slab from our last two storms. Again, it took hard force to initiate failure in faceted snow and none of our Extended Column Test produced propagating failures. Alpine locations in this area have been battered by the wind stripping many areas, and drifting or pressing the snow into dense slabs in others. Our alpine pit may not be truly representative of the slab, weak layer combination in a broad context. We suspect that slopes where the slab is not as thick or dense might be slightly more sensitive to the weight of a rider. Even though we focused our travels to east-facing slopes, as soon as a part of the slope turned more northerly we could feel a drastic reduction in overall snowpack strength and weaker snow below was easy to probe from the surface.