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PROFESSIONAL OBSERVATION FORM
 Start Date: 02.19.17 Name: Davis, Linnet Operation: SAC
 Drainage/Route:  Etna Observed Terrain:  5,600-8,200, W-N Zone/Region:  Wood River Valley
WEATHER OBSERVATIONS
 HN24: 22 cm HST: 45 cm Sky: SCT Precip: S3 Temps:
 Ridgeline Wind: Moderate and Gusty from the SW
 Blowing Snow: M Snow Available for Transport: Small amounts
 Comments: Waves of sun and whiteout. Intermittent periods of S3 strong wind and intense snow transport from the south and southwest. Accumulations of ~1 inch during the tour. Most of our time spent in exposed middle elevations we experienced moderate west wind and light to moderate snow transport.
AVALANCHE OBSERVATIONS
None Reported
 Comments: No new avalanches observed.
SNOWPACK OBSERVATIONS
 HS: n/o 
 Upper Pack: Norths: HST 15-45 cm heavy powder on 1-3 different crusts near the (2/16) interface. Wests: 5-25 cm settled creamy new snow atop soft rain crust.  
 Middle Pack:  
 Lower Pack:  
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:
20-60 cm

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Specific
Terrain
  Primary Concern Comments: Some isolated cracking.
 
Avalanche Characteristics
Character/Avalanche Problem:
Persistent Slab

Layer/Depth:
45 cm

Likelihood of Triggering
Sensitivity:
Touchy

Spatial Distribution:
Isolated
Terrain
  Problem 2 Comments: Some cracking and collapsing. Maybe narrow elevation band.
STABILITY TESTS
 Stability Test Results: No results on western aspects. Heavy settled powder glued to a crust. Norths produced easy shears down 22 cm below last nights snow. Propagating results in facets atop a crust below that down 45 cm: ECTP 16, 19 on FC 1 mm
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Cracking (isolated)    
 Collapsing (isolated)    
 Comments: Localized cracking and collapsing on middle elevation norths and wind-affected terrain in shallow wind slabs.
SNOW STABILITY
 Snow Stability Rating for your observed area: Good Confidence: LOW Trend: Improving
BOTTOM LINE
 Comments: This storm and warm temps have the feel of short-lived spikes in instability followed by rapid healing. Norths were the exception today with some propagating results in 1 mm facets on a buried crust. This crust was the uppermost of three within a 20 cm layer. Unsure when this formed (fluctuation in rain line or warm temps Friday?). Maybe this will only be a problem in a narrow elevation band. Felt comfortable skiing steep wests. Would have been more hesitant in any wind-loaded pockets on norths due to uncertainty in the bond near the (2/16) interface.