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PROFESSIONAL OBSERVATION FORM
 Start Date: 01.18.19 Name: Lundy Operation: SAC
 Drainage/Route:  Copper Mountain Observed Terrain:  6900-8600, SW-W-NW Zone/Region:  Banner Summit
WEATHER OBSERVATIONS
 HN24: HST: 30cm Sky: OVC Precip: Temps:
 Ridgeline Wind: Light and Intermittent from the NW
 Blowing Snow: None Snow Available for Transport: Large amounts
 Comments: Evidence of significant wind transported snow since skier traffic yesterday afternoon.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 1 Jack's Yesterday 2.5 HS ASr W 8600 See photo
 Comments: Avalanche was remotely triggered yesterday by skiers digging a snowpit about 100 feet above the crown in lower angled terrain. It broke on basal facets about 90+cm deep. Avalanche was approximately 200 feet wide and reportedly ran about 1000 vertical feet down the main Jacks gully to where it T's into the main gully coming off the summit.

I could not find a safe spot to do a crown profile unfortunately. I dug about 200 vertical feet lower on a similar aspect - see below - but I did not have time to perform any tests. Not sure they would have been useful given the depth of the weak layer.
SNOWPACK OBSERVATIONS
 HS: 100cm at the highway up to 150cm in mid elevation sheltered terrain. Snowpack obs were limited as I was short on time.  
 Upper Pack: 30cm HST 
 Middle Pack: all 1f to P. No obvious weak layers present but no tests performed. 
 Lower Pack: 20-30cm of 4F- FC and DH, 2-3mm. Dry at the top of the layer. No crusts observed in this pit or while probing in the vicinity of the avalanche crown. I suspect this layer is 12/11 vs. 11/22 but not certain. 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Deep Persistent Slab

Layer/Depth:
12/11, 90+cm

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Widespread
Terrain
  Primary Concern Comments: Forecasted distribution. Only observed mid elevation W
 Comments: Hand pits and poking on solars seem to indicate less of a defined WL near the ground and a fairly strong mid pack. Still wouldn't totally trust solars without more info.

DIdn't observe wind slab problems but would expect them to exist in more exposed terrain based on evidence of wind transport overnight.
STABILITY TESTS
 Stability Test Results:
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: Trend:
BOTTOM LINE
 Comments: Seems like we're moving into a low-probability, high-consequence scenario in this area.
FILE ATTACHMENTS

190118-Copper-Jacks-ASr-Avalanche_resized.jpg
Avalanche on Copper