Aspen
AvalancheDylan Craaybeek · Feb 14, 2023 · Aspen
Weather
Overcast and snowing between S-1 and S5 throughout the day. Periods of the most intense precipitation (S5) did not last more than about 30 minutes. About 14cm of new snow fell throughout the day in West Willow by 15:00 below the treeline. The storm came in with less wind than expected but was still gusting at Moderate speeds at ridgeline and transporting snow.
Snowpack
Thin wind-slabs were quickly developing throughout the day enough to easily trigger very small avalanches in the wind-drifts on slopes steeper than 40 degrees that were no more than 10 feet in width. As the snow continues to accumulate the main concern is for a D1 or a small D2 Wind Slab avalanche to step into persistent weak layers near the ground and take out the whole season's snowpack. A representative southeast-facing snowpit dug near what is locally known as "Juans Way" above the treeline shows a very concerning snowpack on a very popular backcountry. The height of snow (HS) varies between about 90cm to 120cm (deeper in wind drifts) with weak (F-hard on the hand hardness scale), well-developed depth hoar at the bottom of the snowpack resting on a layer of basal ice with a soft slab making up the middle of the snowpack (4F to 1F- hard on the hand hardness scale) that shows clear signs of faceting and losing cohesion but still has all the characteristics of a dangerous slab of a persistent weak layer. The upper portion of the snowpack consists of three to four melt-freeze crusts (MFcr) that are supportable to the weight of a skier on south-facing slopes steeper than about 25 degrees. Extended column tests show propagating failures on the near-surface MFcr on isolation and propagating failures on the basal facet layer within 10-20 taps. The average HS for West Willow was around 90-120cm on southerly slopes and 110-150 on northerly slopes.
Avalanche
Easily triggered very small slabs below cornices and on steep rollovers that did not break wider than 10 feet and about 5-10cm deep. Two or three of them could have been large enough to knock a person off their feet.