Gunnison
SnowpackJohn MacKinnon · Jan 20, 2013 · Gunnison
Weather
Clear skies, strong solar radiation and light northerly winds. Observed a daytime high of -1 at 11,400 ft at 12:30 pm.
Snowpack
Lower angled sunny slopes below treeline are still holding onto surface hoar >5mm. Steeper slopes have melt-freeze crusts with a small layer of facets on top. Overall, shallow and weak snowpack on lower elevation southerly slopes. Profiles at 11,400 ft on a S aspect that had seen some previous wind loading showed a deeper snowpack--HS 50 to 70 cm-- with a bit more layering. Last week's storm snow was resting on a facet/crust combo--this layer produced consistent "drops" during compression tests just below the crust on facets. Top layer is 10 cm of F+ snow. Compression tests also showed consistent "drops" on a 2 mm facet layer that makes up the bottom 10 cm of the snowpack. Another round of profiles at 11,800 in a wind-loaded area on a S aspect showed a much deeper and complex snowpack. HS ranged from 100 cm to 120 cm. Jan. 11th storm snow is over 20 cm deep and 1F hard. This layer is resting on a weak layer of near surface facets and produced consistent sudden results during snowpack tests. Of note: ECTP 1 on the Jan 11th facet layer. Older wind and snow events had created a series of 1F to P hard slabs in the middle of the snowpack and deeper weak layers continue to exist . Basal weak layers were not showing any results in ECTS or CTs but a deep tap test produced a sudden collapse on the depth hoar-- DTH (SC) x 1. We observed cracking in the upper snowpack on the Jan. 11th interface while skiing near and above treeline. Below treeline, melt-freeze crusts on southeast facing aspects gave way to moist snow on steeper south and southwest slopes. I don't expect this area will much more traffic until we get some more snow!! John MacKinnon