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PROFESSIONAL OBSERVATION FORM
 Start Date: 02.19.19 Name: Davis, Preuss Operation: SAC
 Drainage/Route:  Quigley Canyon - Patterson Pk Observed Terrain:  5600'-8350', W-N-E Zone/Region:  Wood River Valley
WEATHER OBSERVATIONS
 HN24: HST: Sky: FEW Precip: Temps:
 Ridgeline Wind: Light and Intermittent from the NW
 Blowing Snow: Prev Snow Available for Transport: Small amounts
 Comments: We stayed in the sun for the majority of the day despite cloudier looking conditions all around us.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 2 Patterson shoulder Within past week 1.5 HS N NE 6500' Reported earlier by skiers on the nordic trails
 2 Head of Democrat Gulch Within past week 2 N E 7500'-7700' One on the Democrat side and one on the Deer Creek side.
 1 Peak on S. side of the road where Slaughterhouse Creek Road turns north Within past week 2.5 N N 8200' Wide and deep looking persistent slab.
 2 East of Patterson Ridge Within past week 2 N NW 7300'
 Comments: We also observed at least 6 or 8 older smaller (up to D1.5?) wind slabs. Many of these failed on the steep, cross-loaded arms of Patterson and in Slaughterhouse due to funneled west wind.
SNOWPACK OBSERVATIONS
 HS: 106 cm on moderately wind affected NW @ 7,200' 
 Upper Pack: 106-50, 4F- to 1F. (2/2) at 50 cm was a thin MFcr. 
 Middle Pack: 50-20, stronger old, rounding FC 
 Lower Pack: 20-GR, F, 4-5 mm moist DH 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Persistent Slab

Layer/Depth:
40-150+

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Widespread
Terrain
  Primary Concern Comments: There was no PS problem at lower elevation in this drainage. We did not look on souths.
 
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:
20-100 cm

Likelihood of Triggering
Sensitivity:
Unreactive

Spatial Distribution:
Specific
Terrain
  Problem 2 Comments: Cross-loaded and lee slopes from west and northwest wind.
STABILITY TESTS
 Stability Test Results: Moderately wind affected NW @ 7,200': ECTP20, CPST 26/100 end, PST 29/100 end
SNOW STABILITY
 Snow Stability Rating for your observed area: Good Confidence: HIGH Trend: Improving
 Comments (aspects and elevations of instability, etc): We felt MODERATE at middle and upper and LOW at lower was accurate for this drainage.
BOTTOM LINE
 Comments: A general lack of a slab at lower elevations in this location along with thick crusts and worked over facets near the ground presented no hazard. There was considerable wind affect at middle and upper elevation but the slabs felt old and dead on the ascent and descent. Poor snowpack structure and test scores gave us pause but it seems likely that trigger points are harder to come by.
FILE ATTACHMENTS

190219_Patterson_01.jpg
Democrat side.

190219_Patterson_02.jpg
One on the Democrat side and one on the Deer Creek side.

190219_Patterson_03.jpg
Wide and deep looking persistent slab.

190219_Patterson_05.jpg
East of Patterson Ridge