Date of Observation: 02/13/2021
Name: Zach Guy
Zone: Northwest Mountains
Location: Anthracite Mesa
Aspect: South West, West
Elevation: 9500 – 11200′
Avalanches: Limited visibility but we spotted a handful of natural slab avalanches that ran in the past 24 hours. A number of D1 to D2s below treeline (most appeared to be persistent slabs). Several larger ones off of Schuykill Ridge, I believe at least one more D3 that snapped trees and hit the valley floor from the “Great Wide Open”. Light was too flat to see crown but debris looked fresh.
Weather: Snowfall started around noon – moderate to heavy (S2 to S5) throughout the rest of the day. About 4″ or 5″ of accumulation by sunset. Light ridgetop winds with moderate gusts and some light snow transport. Winds were channeling up valley out of the south.
Snowpack: About 20″ of storm snow since Friday morning. We only observed a few signs of instability underfoot, but they were quite alarming: huge collapses and shooting cracks opening up hundreds of feet away. Test pit on a southwest aspect at 10,300′ showed hard propagating results at the 2/3 crust and 1/19 crust/facet layer. The latter is three feet deep. The 12/10 layer was about 5 feet deep, and sadly, still fist hard. Crappy structure, even for a deeper snowpack.
Photos:
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- Snow pit on SW aspect showing propagating results on several deep layers
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- We remotely triggered this shooting crack from over a hundred yards away and from below the slope
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- D2, E BTL above Slate River
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- Fresh slabs on Schuylkill Ridge
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- Fresh slabs on Schuylkill Ridge
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- D1 slab near Happy Chutes (NE, BTL)
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- D1.5 slab above Peanut Lake Road (NE, BTL)
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- Recent slabs above the Slate River, D2, E/NE NTL
