Aspen
SnowpackDylan Craaybeek · Dec 27, 2022 · Aspen
Weather
34F at the trailhead around 8300ft. at 10:00 with Broken cloud coverage and a Light breeze. Increasing temperatures throughout the day reaching 44F at the trailhead by 15:30. The storm arrived around 14:30 above 12,000ft. with visibility decreasing to less than a mile and Strong westerly winds then quickly transitioning from S-1 to S2 snowfall just west of Garrett Peak.
Snowpack
Snow surfaces were fairly weak on all slopes with moist facets below around 9,000ft., some small surface hoar development on wind-sheltered slopes, and dry near-surface facets on all open slopes. The slab was noticeably weaker and more faceted on slopes with a lower leaf area index and ski penetration almost doubled as well as far fewer shooting cracks and collapses even though the slab was similarly thin to slopes with denser tree coverage. Extended column tests (ECT) in these more open meadows showed non-propagating failures on the mid-November dry spell layer in 10-20 taps while ECTs on wind-loaded or slopes with denser tree coverage all showed propagating results in 20-30 taps. There was a noticeable difference in snow moisture right around 9500 ft. changing from Dry to Wet in just a few hundred feet. Below this freezing-line melt-freeze crusts will develop on the snow surface on most slopes even shadier ones with the warm ambient air temperature. There was no visible snow transport along ridgeline because there is almost no snow left to transport. Most west and northwest-facing slopes above the treeline are entirely scoured of all snow. There are three most likely layers of failure for most avalanches around this area with the incoming warm, dense snowfall: the weak snow surface once the new snow develops a slab which will produce mostly D1 and D2 avalanches, within the top 30cm of the snowpack in the near-surface facets and the lower and more dense portion of the slab could act as a bed surface (producing mostly D2's), and on the mid-November dry-spell layer breaking down to the ground and producing D2's to D3's later in the storm once the snowfall reaches around 1.25 inches of snow water equivalence (SWE).