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PROFESSIONAL OBSERVATION FORM
 Start Date: 03.08.17 Name: Savage Operation: SAC
 Drainage/Route:  McDonald Peak area (Cabin Ck-S Fork Vat Ck divide) Observed Terrain:  7000-9200', NW-E-S Zone/Region:  Sawtooth Mountains
WEATHER OBSERVATIONS
 HN24: ? HST: 50cm Sky: X Precip: S-1 Temps: 34F road, 26F alpine
 Ridgeline Wind: Strong and Gusty from the W
 Blowing Snow: M Snow Available for Transport: Large amounts
 Comments: Moderate gusty winds below treeline/about 9000'...strong in alpine. Snowing S-1 to S1 from 1330-1430 hrs.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
SNOWPACK OBSERVATIONS
 HS: 7800'=280cm, 8300'=310-330cm, >8600'=deep 
 Upper Pack: Surface=thin wind crust on exposed mid elevation, wind slab upper elevations, 5cm temp or solar crust below 7700'
Then 40-50cm of PP and DF with a density change around 10cm down, well graded going F to 4F
Then sun crust and FC above on E-S
Then RG 
 Middle Pack: Not observed more than 70cm below surface 
 Lower Pack: Not observed 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:
30-100cm

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Widespread
Terrain
  Primary Concern Comments: Slabs getting thick and dense but limited tromping showed them to be pretty stubborn.
 
Avalanche Characteristics
Character/Avalanche Problem:
Persistent Slab

Layer/Depth:
3/3 crust +FC/50cm

Likelihood of Triggering
Sensitivity:
Unreactive

Spatial Distribution:
Specific
Terrain
  Problem 2 Comments: Could call it persistent or storm slab...I didn't see a big problem here but it does involve crust and FC.
STABILITY TESTS
 Stability Test Results: Multiple CT1, BRK, 10cm down: multiple CT6-7, BRK, 14cm down: CT14, RP, 30cm down: CT16 and 24, RP, 50cm down on FC above crust: ECTN1, 10cm down: ECTN7, 14cm down: ECTN13, 50cm down
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Cracking (isolated)   Length: 2m
 Comments: Terrible visibility, but might have seen a D1.5 debris pile that stopped mid-track in wind loaded alpine path, N/NW facing
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: LOW Trend: Worsening
 Comments (aspects and elevations of instability, etc): CONS at upper elevations due to widespread wind slabs, growing today. MOD at middle and lower elevations (widespread wind affects but not as much loading and no glaring weak layers).
FILE ATTACHMENTS

170308_McDonald_cornice_windslab_labeled.jpg
Wind affects on ridge 9100 feet

170308_McDonald_8300_ESE_pit_labeled.jpg
Labeled pit with density change and FC/crust combo

170308_McDonald_8300SE_ECTN_resized.jpg
ECTN on FC/crust ESE, 8300 feet