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PROFESSIONAL OBSERVATION FORM
 Start Date: 02.05.19 Name: Davis Operation: SAC
 Drainage/Route:  Trail Creek - Morgan Ridge Observed Terrain:  6000-8000', S-W-N Zone/Region:  Wood River Valley
WEATHER OBSERVATIONS
 HN24: HST: Sky: VAR Precip: Temps:
 Ridgeline Wind: Light and Intermittent from the Variable
 Blowing Snow: Prev Snow Available for Transport: Large amounts
 Comments: The day started hazy with some sun breaks by later in the afternoon. The wind also seemed to increase in the afternoon from the north. More obvious wind affect was apparent due to down canyon wind in Croy Canyon.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 2 Morgan Ridge Today 2 HS AS NW 7000' A collapse on the ridge produced a crack that traveled 1,000' to the near side of the slide and a half mile in total releasing two separate slides. Both were ~700' wide and 2-4' deep. One stopped on a bench and the other ran ~900 vertical to the valley floor. The avalanches failed in both the 45 cm recent wind slab, another older/weathered persistent slab and in the FC/DH at the ground.
 1 Mine Bender Yesterday 2 N NW 8600' Looked a little fuzzy, may have occurred during the intense squall on the night of (2/4)
 3 Della Today 1 SS N E 6-6500' Peelers failing mid and late storm from the ridge/cornice at the mouth of Croy.
 Comments: I had decent visibly from Morgan ridge and saw no other recent naturals.
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Persistent Slab

Layer/Depth:
60-80 cm

Likelihood of Triggering
Sensitivity:
Touchy

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

Layer/Depth:
45 cm

Likelihood of Triggering
Sensitivity:
Reactive

Spatial Distribution:
Specific
Terrain
  Problem 2 Comments: 
STABILITY TESTS
 Stability Test Results:
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Cracking (widespread)    
 Comments: I could not walk more than 40' before collapsing another pocket. These occurred on a west aspect with little to no wind affect. As I ascended the ridge into more connected wind-affected terrain the collapses traveled further, ultimately up to a half mile to trigger the slide shown in the photos.
SNOW STABILITY
 Snow Stability Rating for your observed area: Poor Confidence: HIGH Trend: Steady
 Comments (aspects and elevations of instability, etc): I was certainly traveling like it was HIGH and avoiding avalanche terrain or slopes connected to steeper pockets. The overall lack of recent naturals, and the lower odds of finding stiffer slab outside of the lee of the wind-affected ridge I was on had me lean toward a meaty CONSIDERABLE in this middle elevation terrain and MODERATE at low.
BOTTOM LINE
 Comments: I was surprised to get as much collapsing as I did at lower elevations. I assume the propagation here was aided by the thin Mfcr under the storm snow. I'd be curious to see how SW-S-SE facing slopes handle some additional wind loading if the wind kicks up from the NW. Trail breaking was heinous anywhere but on a wind slab and this area continues to harbor a trap door, rotten structure.
FILE ATTACHMENTS

190205_Morgan_TriggerPoint.jpg
Trigger point

190205_Morgan_03.jpg
View from nordic trails

190205_Morgan_01.jpg
Wind slab and older persistent slab pulled out and gouged to DH at the ground.