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PROFESSIONAL OBSERVATION FORM
 Start Date: 02.05.19 Name: Lundy Operation: SAC
 Drainage/Route:  Vanity Creek Summit Observed Terrain:  7400-8800', ~W Zone/Region:  Banner Summit
WEATHER OBSERVATIONS
 HN24: ? HST: 45-50cm Sky: X Precip: S-1 Temps:
 Ridgeline Wind: Light
 Blowing Snow: None Snow Available for Transport: Large amounts
 Comments: We entered the field late morning with obscured skies and S1. Snowfall tapered off in the early afternoon, and clouds began to lift. Temps dropped and the wind shifted NW.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 1 Above Langer trailhead Yesterday 2 SS N NE 8000
 Comments: See attached photo. Light was poor and details are hard to discern. Can't say if it broke into deeper layers or it was a windloaded slope that ran on the 2/2 interface. Fairly wide propagation.
SNOWPACK OBSERVATIONS
 HS: Pit at 8400', W: HS 165cm. See attached photo 
 Upper Pack: 50cm HST, 4F+ at base of storm snow - definitely settling into a slab
5cm of ~F+ FCsc (2/2 interface) 
 Middle Pack: 1F and 1F+ RG 
 Lower Pack: 30cm rounding FC/DH, 4F and dry at the top of the layer 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Storm Slab

Layer/Depth:
2/2, 45-50cm

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Widespread
Terrain
  Primary Concern Comments: 
 
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:


Likelihood of Triggering
Sensitivity:


Spatial Distribution:

Terrain
  Problem 2 Comments: Didn't observe this problem directly but had 2 medium collapses on a subtly wind loaded mid elevation shoulder
 
Avalanche Characteristics
Character/Avalanche Problem:
Deep Persistent Slab

Layer/Depth:
12/11 - 130cm

Likelihood of Triggering
Sensitivity:


Spatial Distribution:

Terrain
  Problem 3 Comments: no new data other than presence of layer in pit
 Comments: Suspect that wind slab is the primary problem in this area but didn't observe it directly. No obvious secondary problem - most concerned about where the 2/2 interface (FCsf) is weaker, and also the addition of 2+" of water weight to deeper weak layers. There were some shears within the storm snow but these didn't seem particularly concerning.
STABILITY TESTS
 Stability Test Results: CT19 SC, ECTNH on 2/2 FCsf layer 50cm down
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Cracking (isolated)    
 Comments: Numerous very small, muffled collapses - either within storm snow or at the 2/2 interface. Two medium collapse on a mid elevation, wind affected sub-ridge that were on the order of 10-15m in diameter.
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: Trend:
 Comments (aspects and elevations of instability, etc): Low confidence since we didn't directly observe the wind slab problem and still leery about 2+" of new water weight.
BOTTOM LINE
 Comments: We stuck to avalanche proof terrain which may have been a bit conservative for the conditions, but concerned about the new load added to deep weak layers as well as the storm snow on a potentially weak and variable old snow surface.
FILE ATTACHMENTS

190205_vanity_snowpit.jpg
Snowpit at 8400', W aspect.

190205_vanity_avalanche.jpg
Fuzzy photo of fresh avalanche viewed from across the valley. Difficult to make out many details.