Vail & Summit County
SnowpackAndrew McWilliams · Mar 25, 2024 · Vail & Summit County
Weather
Light snow all day with periods of heavier snow. Light winds from the north and temperatures in the teens.
Snowpack
Near town, there was only two or three inches of new snow. When I ascended to around 11,000 feet, there was closer to six to eight inches of new snow. There was likely an additional two or three inches of accumulation while I was in the field at upper elevations and no new snow on my car in town. With light winds and low-density snow, there was no slab development within the new snow where I traveled. If the wind speeds increase, plenty of snow is available for transport and new slabs will be easily developed. You could easily trigger sluffs within the new snow on very steep slopes. On southerly slopes, these were running on stout melt-freeze crusts, on northerly slopes they were running on a layer of decomposing fragments and facets that formed during the last dry spell. I dug snowpits on northerly slopes at both ends of the near treeline elevation band. The early February (2/2) weak layer and dust layer were obvious in both pits. The 2/2 layer is buried 80 to 100cm below the surface. In one pit there was no result on this layer in an Extended Column Test (ECT); in the other, I got a propagating result after two blows from the shoulder in an ECT. Where there was no result, the layer was about 5cm thick, composed of rounding facets, and about a meter deep. Where I got a result, the layer was thinner, the faceted grains showed little rounding, and it was 80cm deep. I also got a propagating result at the basal facet interface after seven blows from the shoulder in one of the pits in an ECT. The basal facets were dry, 3mm in size, rounding, and four-finger hard on the Hand Hardness Scale. On a southeast slope just above 12,000 feet, I noticed a two to three-inch thick melt-freeze crust (which includes the dust) below the most recent snow. In this pit (the last one I dug) the storm snow was 25 cm or 10 inches deep. I did not notice any faceted grains at the interface of the new snow and the old surface - the thick melt-freeze crust. There was a thin and easily breakable melt-freeze crust within the new snow, possibly from a short period of sunshine during the storm. This crust likely won't last long when the sun comes out again. In a snowpit, there was a non-propagating result in an ECT on that crust and at the new-old interface likely due to the lack of slab quality to the snow above and the fragility of the upper, thin crust. There were ice bodies and a thin ice layer about 15cm below the thick dust crust suggesting melt-water had reached that depth during the last dry and warm period. The height of snow in this pit was about 120cm and the signs of melt-water moving through the snowpack were found down to about 60cm from the ground. Basal facets made up about the bottom 30cm of the snowpack in this location. The 2/2 layer here was a decomposing melt-freeze crust that was becoming difficult to distinguish from the slab around it.