Gunnison
SnowpackEvan Ross · Jan 14, 2025 · Gunnison
Weather
Light winds were still transporting small amounts of snow above 11,000ft. Cold and Scattered cloud cover.
Snowpack
Upper Cement Creek and Hunter Hill are, again, a great example of a continental snowpack. The snowpack primarily varies from shallow and weak to hard and moonscape. Ideal conditions for a reactive persistent slab still exist somewhere, but the number of locations that would meet those conditions has greatly decreased as slabs have faceted away and/or previous winds have wreaked havoc on the snowpack. The most reactive snowpack that I found was often near the valley bottoms or sometimes out of the valley bottoms on other low-angled slopes. In those locations, the slabs were faceting away, but the weak layer was so bad that the upper snowpack was still collapsing into the weak layer. The weak layer would consist of large-grained and chained facets, very large surface hoars, or collapsible crusts into large-grained facets. There were some fascinating slope-scale rolling collapses. On multiple occasions, when I found these conditions, I would move right next door to a steeper test slope, and the snowpack would go quiet. Between 10,000 feet and 11,600 feet, the average slab depth over the December drought layer was 40 to 45cm thick. These slabs all appeared to lack enough cohesion to propagate. Where they would be problematic would be somewhere that they are a little thicker or have a little wind effect. By the time I was at 11,600ft in the Hunter Creek area, the snowpack was heavily redistributed by previous winds, and slabs were very hard. You would have needed to find the right trigger point to pop one of these hard slabs. I stopped to check out one old slab on a south-facing slope at 11,700ft. From afar, this looked like a wind slab that failed around the 1/10 wind event; however, up close, it was clear that this slab failed deeply in the snowpack and released on 1.5mm facets above a thick crust created during the December drought. The weak layer on top of this crust was 3cm thick and 4F- hard. This helped further confirm that many of the avalanches that failed on southerly aspects during last weekend's wind event failed several layers deep on this old, weak layer. I dug on another south-facing slope in the same area that wasn't wind-loaded, and the same weak layer was present, but the 35cm of snow that was above the weak layer was faceting away and lacked a slab. That 2nd location was a 30-degree slope.