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PROFESSIONAL OBSERVATION FORM
 Start Date: 03.01.18 Name: Wieland, VandenBos Operation: SAC
 Drainage/Route:  Lake Ck Observed Terrain:  6200-8400 Zone/Region:  Wood River Valley
WEATHER OBSERVATIONS
 HN24: 5-10cm HST: 5-10cm Sky: X Precip: S1 Temps:
 Ridgeline Wind: Light from the SE
 Blowing Snow: Snow Available for Transport:
 Comments: Afternoon tour. Brief lull in storm around 4 PM with snowfall picking back up around 5 PM. Pushing 10cm HN by days end. Calm to light winds.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 1 Triple Pk 1 N W 7900 Near avalanches in Savage Ob.
SNOWPACK OBSERVATIONS
 HS: 60-80cm in west facing terrain we skied. Snowpack obs on West aspects 
 Upper Pack: 30-40cm PP/DF from recent storms 
 Middle Pack: 1 cm crust with some ~6cm FC above. Crust was quite firm ~8000', but aspect dependent.  
 Lower Pack: 15-20cm stronger DH with 20cm Fist DH under crust.  
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Persistent Slab

Layer/Depth:
30-40cm

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Widespread
Terrain
  Primary Concern Comments: Considerably worse on slopes that had been cooked less by the sun. However, structure is pretty marginal around the compass (wherever there is an actual snowpack) and will not react well to a significant load, regardless of aspect. Dumping in Ketchum (~10pm), its hard to imagine that the WRV snowpack is holding up well to this rapid loading, particularly on slopes >~35.
 Comments: Not enough wind transport, nor enough of an overlying slab to be a problem yet. Given rate of precip this has the potential to change quickly
STABILITY TESTS
 Stability Test Results: ECTN's in HST interfaces and on FC above/below more deeply buried crust. Seemed like not enough slab (yet) in pit locations. Recent avalanches in the area point to there being enough slab and/or enough of a weak layer in some locations.
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Cracking (widespread) Depth: 2/14, 30-45cm down  
 Collapsing (widespread) Depth: 2/14, 30-45cm down  
 Comments: Lots of cracking and collapsing on just about every slope we touched.
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: Trend:
BOTTOM LINE
 Comments: Just an awful snowpack structure on most shaded slopes (and pretty darn marginal on the solars too). Some pretty touchy interfaces in recent storm snow that were fracturing while breaking trail in untouched snow and while skiing above tracks. With the snow that is forecasted tonight things will definitely be reactive in the morning. A snowpack like this is months in the making. Belly button deep powder is uncommon, but finding a snowpack that looks like this in March is exceedingly rare.