Date of Observation: 12/22/2022
Name: Eric Murrow
Zone: Southeast Mountains
Route Description: North through east slopes below Snodgrass Trailhead down to the East River.
Observed avalanche activity: Yes
Avalanches: Observed one natural avalanche from overnight on a well-drifted northeast slope below treeline and remotely-triggered two slabs on northeast slopes below treeline. All three were D1.5 and broke at the old, faceted snow surface prior to wind event.
Weather: Decreasing cloud cover throughout the day and reduction in wind speeds by late morning. New snow accumulation roughly 4 inches, but hard to say given the impressive wind event.
Snowpack: We went hunting for fresh slab formation below treeline on shaded aspects. Each time we found a fresh, hard wind deposit the slab collapsed and cracked. On two steep features, avalanches released in the upper snowpack around 1 foot deep on average, but some portions of crowns exceeded 2 feet. The distribution of fresh surface slabs seems fairly isolated below treeline, but touchy to the weight of the person when encountered. Faceted grains in the weak layer were around 1mm in size. Many nearby slopes with similar aspects were scoured without recent wind loading. A smooth, lens shape and hard surface made it fairly easy to identify sensitive wind drifts.
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- A quick look at remotely-triggered avalanche. The avalanche failed on faceted grains beneath the recent storm/wind event. It did not step down even though there is clearly Persistent Slab structure present below.
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- Looking up at the remotely triggered avalanche and an immediately adjacent natural avalanche from overnight.
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- Another remotely triggered avalanche in stiff, wind drifted snow below treeline. This avalanche ran on the faceted grains at the new/old interface.
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- Blowing snow was visible through much of the afternoon but slowed before sunset.
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- Impressive amounts of erosion on westerly aspects near and above treeline near WSC Peak.
