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Touchy Cornices and Wind Slabs
On a tour up Green Butte Ridge out of Bunny Flat, no wind effect was seen below treeline. Winds were calm to light. Column tests on a sheltered, northwest aspect yielded hard failures about 13 inches (34 cm) down on a weak interface (CT21). Extended column tests yielded no failures or propagation (ECTX). Ski cuts on small cliff areas were mostly unreactive, though a small, barely-notable, slough was triggered.
When transitioning to above treeline, wind effects were evident. Cornices were forming and broke upon approach. Extended column tests within drifting snow failed upon isolation (ECTPV). Four-finger-hard cohesive snow sat atop fist-hard snow. Failures occured a few inches below the fist-hard snow on a thin, visible, fist-hard-minus layer (see pic below). This was almost 3 ft down. Wind loaded areas could easily be described as "touchy".
Broadway Ridge was wind effected and becoming scoured.
Similar conditions were reported on Gray Butte.
- Observation Location: Green Butte Ridge
- Elevation: 7,000 ft - 8,000 ft
- Date: 20211216
- Time: 13:00
- Observer: Aaron Beverly
- Sky Conditions: Obscured (X)
- Current Precipitation: Type - SN, Rate - S2
- Air Temperature: 14 °F
- Surface Penetration: Ski penetration (PS) = 3-4 in ([?] cm)
- Total Snow Depth (HS): [?] in ([?] cm)
- 24-hour New Snow Depth (HN24): [?] in ([?] cm)
- 24-hour New Snow Water Equivalent (HN24W): [?] in ([?] cm)
- Wind Direction: W
- Wind Speed: Light (L), 1-16 mi/hr -- Moderate (M), 17-25 mi/hr
- Column & Block Tests:
- On a NW aspect @ 7,880 ft: CT 21 ↓ 34 cm x 2; ECTX
- On a SE aspect @ 8,080 ft: ECTPV ↓ 95 cm