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ADVANCED OBSERVATION FORM
 Start Date: 12.30.17
 Drainage/Route:  The knob - Summit Creek, Pilot Peak Observed Terrain:  6000-7600 feet, N, NE, E, SE, S aspects Zone/Region:  Mores Creek
WEATHER OBSERVATIONS
 HN24: 3 cm HST: 3 cm Sky: SCT Precip: S-1 Temps: -4 Deg C
 Ridgeline Wind: Moderate from the SW
 Blowing Snow: M Snow Available for Transport: Small amounts
 Comments: Thursday night there was a rain event at all elevations. Widespread formation of thin rain crust at all elevations and aspects.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
  None
SNOWPACK OBSERVATIONS
 HS: 63 cm at snowpit location - Below the knob 7400 feet NNE aspect, 29 degree slope. 
 Upper Pack: 25 cm Persistent slab in top of 2.5 mm facets. Check snowpit at https://snowpilot.org/node/4893
At this pit location the facet layer was 2-3 cm thick, much less than higher in the slopes where we previously documente a weak layer of 9-10 cm. 
 Middle Pack:  
 Lower Pack:  
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Persistent Slab

Layer/Depth:
25

Likelihood of Triggering
Sensitivity:
Touchy

Spatial Distribution:
Widespread
Where did you find this problem?
  Primary Concern Comments: 
STABILITY TESTS
 Stability Test Results: CTMQ1(SC), ECTP14, PST20/140 (Arr), CPST25/90(End)
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Collapsing (widespread) Depth: 25  
SNOW STABILITY
 Snow Stability Rating for your observed area: Fair Confidence: MODERATE Trend: Steady
BOTTOM LINE
 Comments: The warm temps of Thursday did not impact the persistent slab structure present at MCS. It will inevitably get loaded during a future storm. And this is a rare type of instability for this area. It appears to be the result of a snowpack at 50% of average rarely seen at MCS (last time more than 30 years ago). I am concern that once we get a big precipitation event, recreationists might not realize the danger posed by the persistent slab problem.