Lundy Cyn, Roadside Attraction - Persistent Weakness

SNOWPACK OBSERVATION
Lundy Cyn, Roadside Attraction
Submission Info
Forecaster
Tuesday, March 6, 2018 - 2:45pm
Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Lundy Cyn, Roadside Attraction 38° 1' 13.08" N, 119° 12' 28.08" W
Snowpit Observations
More detailed information about the snowpack: 

Observer: d lewis
Date: Mar 6, 2018, 3:00 PM
Loc: Lundy Cyn, Roadside Attraction Plus
Lat/Lon:38.0203, -119.2078
Elevation: 9400 f
Aspect: NE Angle: 27°
Signs of Instability: Shooting Cracks, Whoomphing
Sky Cover: -SCT
Precipitation: No Precipitation
Wind Speed: Calm, subjective
Current Temp:-2.5°C
Blowing Snow: None
Snow Depth: 95cm
New Snow Storm:56cm 
Snow Temperature 20cm:-7.5° C 
Boot Penetration: 65cm

Comments:

Toured up and around into more sheltered terrain looking for persistent facets prior to the 3/1 storm. Found what I was looking for on sheltered or steep north to northeast aspects above 9000'. Consistent 5-40 cm well developed facets from ground up, capped by ~50-70 decomposing fragments trending to near surface facets in the top ~15-25 cm. Test results failed consistently just below the old / new interface. At the trailhead spoke to a local rider, he mentioned a whoomph above the plateau ~9000' on northeast aspect. Probing from 9000' to 9400' on sheltered or steep N-NE terrain and likely above to ~10000' +/- found facets from prior to the 3/1 storm. Depth varies on aspect, elevation, exposure to wind, and protective landcover. On ascent, saw signs of collapse (~20') both sides of the skin track (NE, 9300'). Consistent results just below the old/new snow interface. Potential for deep release. On descent, small collapse on NE aspect ~8800', 25 degree slope. Top of Roadside Attraction (~8300') snow is generally new snow (40-70cm), over shrubbery, scattered rocks and boulders. Outrun below ~7700' beginning to retreat under the March sun with sagebrush poking through the limited snowcover. 4 Stability Tests: CT24 Q1 39cm Failed below a decomposing melt/freeze crust on course facets (4mm+). CT26 39cm CTV Q2 39cm ECTP25 Q1 39cm SC. Melt freeze crust forming on E-S-W aspects. Maturity depends on angle, duration of sun exposure, and elevation. Still soft on steep or shaded NW-N-NE aspects

 

 

Snowpit or crown profile photo or graph: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Calm
Precipitation: 
None
Air temperature trend: 
Cooling
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 
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