Aspen
AvalancheBrian Lazar Colin Mitchell · Mar 1, 2017 · Aspen
Weather
Clear skies, and very light winds. Cool temperatures, but the solar radiation was strong, and it felt a lot warmer than it was.
Snowpack
Average height of snow is well over 3 meters. In some places it's over 4 meters deep. HST 25" at the trailhead, 30"+ up high. The new snow had a 4F- slab 3-5" thick at the surface, likely from yesterday's post storm winds and or/settling in the upper snow surface with the strong radiation. The rest of the storm snow was F hard and unconsolidated. Avalanche concerns are limited to the top 150 cm or so of the snowpack, and some layering is present. We dug test pits on north, east and southwest aspects. North and east aspects had a layer of small-grained (0.5 mm) facets down about 60 cm which failed with a compression test, CTM SC. We also got compression test results within the storm snow, down about 50 cm. The failure layer was DF grains, probably the low-density snow that fell Sunday night. This is the likely failure layer for the storm slab avalanches in the area. A widespread natural storm slab avalanche cycle occurred on all aspects near and above treeline, and all avalanches were limited to the new snow. Nothing stepped down to the buried facets.
Avalanche
Natural storm slab avalanches occurred on many slopes in and around the Marble area. All of the slides were limited to the storm snow, with the possible exception of one on Raspberry Peak, which appeared to be a persistent slab. Many loose snow slides had occurred at all aspects and elevations.