Negatives

SNOWPACK OBSERVATION
Negatives
Submission Info
Forecaster
Thursday, April 5, 2018 - 2:45pm
Red Flags: 
Recent avalanche activity
Rapid warming
Obvious avalanche path
Negatives, June Lake 37° 43' 37.2" N, 119° 5' 42.36" W
Snowpit Observations
More detailed information about the snowpack: 

Observer: d lewis
Date: Apr 5, 2018, 3:49 PM
Loc: Negatives
Lat/Lon:37.7270, -119.0951
Elevation: 10550 f
Aspect: NNE Angle: 34°
Signs of Instability: Recent Avalanches
Sky Cover: -BKN
Precipitation: No Precipitation
Wind Speed: Calm, beaufort
Current Temp:3°C
Blowing Snow: None
Snow Depth: 160cm
Snow Temperature 20cm:-2° C 
Boot Penetration: 10cm 

Stability Tests: CT23 Q3 115cm Preserved stellars CT22 Q2 106cm CT23 Q3 65cm ECTX 0cm

Comments: Toured up to the Negatives to assess the N-NE aspects for warming and Loose Wet conditions. Snow thawing rapidly on all but N-NE aspects in the AM, by mid-afternoon, mid elevations (>9800' and below) becoming isothermal and unsupportive with ski pen 15 cm, boot pen 25cm. Above 9800', 10 to 15 cm ski pen and supportive. Above ~11,000’ snow is just beginning to transition to melt freeze on N-NE aspects, .5 to 1mm grain size, moist. ~Air Temps varied from 3 to 6 C. T20 temps 0 on all but N-NE aspects (above~9800’, -1.9C). Spring snow at the surface on all aspects. Pole probing: W-S-E aspects 5 to 10cm poly crystals (4F) over melt freeze crust (1F+/P-), over moist rounds for ~40 to 50cm overlaying a firm mid-pack. Noted one D1 started by rock fall on SE aspect, ~9800’. The rocks that started it were a greater hazard than the D1. No other activity noted. On shaded and/or steep N-NE aspects, the snow remains dry and cool below the top ~10 to 15cm of surface snow, surface snow moist to wet. Compression Tests hint at some subtle weaknesses within the top ~75 cm but results were inconsistent, Extend Column Tests negative. Found the Graupel layer from early March, still well preserved but not consistently reactive. Further testing yielded failures on preserved Stellars but again inconsistent. Final test failed at the facet round interface but unable to duplicate results. Test slopes yielded only small surface instabilities may, very localized and sliding short distances with limited rollerballs. Very steep solar aspects may yield larger results where there is deep thawing, but not tested.      

 

 

Snowpit or crown profile photo or graph: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Calm
Precipitation: 
None
Air temperature trend: 
Warming
More detailed information about the weather: 

AM - mostly coudy with mid and upper level couds becoming partly cloudy mid day. Cloud cover increased late afternoon woth light showers over the upper elevations to the north of Tiorga pass. Winds at ridgetop - Light SW, with moderate gusts.  

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