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PROFESSIONAL OBSERVATION FORM
 Start Date: 03.09.19 Name: Lundy, Guess Operation: SAC
 Drainage/Route:  Frenchmans Observed Terrain:  Most obs were focused on SE and SW, 7800-9000' Zone/Region:  Smoky & Boulder Mountains
WEATHER OBSERVATIONS
 HN24: HST: 25cm Sky: BKN Precip: Temps:
 Ridgeline Wind: Moderate from the W
 Blowing Snow: L Snow Available for Transport: Small amounts
 Comments: Day started out with much less cloud cover than forecast, but temps were cool and there was little effect on solar slopes. Clouds finally moved in around 1300 and by the end of the day the mountains were obscured. There were a few flurries at times. Temps seemed to decrease with cloud cover.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 3 Frenchmans Within past week 2 SS N NW 9400 At least 3 shallow wind slabs on a steep feature at the head of the drainage. Crowns were mostly blown in but one of the slides ran about 1000 vertical.
 1 Frenchmans Within past week 2 SS N N 9600 About a foot deep and 300 feet wide. Likely wind loaded. See photo.
 1 Frenchmans Older than a week 2.5 HS N NW 9400 Old deep crown, but hard to say if it went on basal FC or not. Propagation wasn't very extensive. See photo
 Comments: The main naturals I saw were on shady aspects, which didn't necessarily fit with the facet/crust pattern we've seen elsewhere.
SNOWPACK OBSERVATIONS
 HS: 8800', SE, 26*: HS 250cm, HST 25cm. Obs below are from this location 
 Upper Pack: 25cm recent HST, already beginning to facet. F+ at base of HST
1cm small FCsf, F
1cm MFcr P (3/6 layer) 
 Middle Pack: Very strong midpack with hardness greater than P 1m down (see photos). Probed for 2/2 crust and found it 175cm down. No discernable layers or weakness. 
 Lower Pack: n/o 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:


Likelihood of Triggering
Sensitivity:
Unreactive

Spatial Distribution:
Specific
Terrain
  Primary Concern Comments: Wind slabs at ridge level were not extensive, but those that did exist were unreactive to stomps and ski cuts
 
Avalanche Characteristics
Character/Avalanche Problem:
Persistent Slab

Layer/Depth:
3/6 - 25cm

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Specific
Terrain
  Problem 2 Comments: I only observed this layer on SE and SW (layer described in snowpack obs above), but pattern of activity in this drainage indicates there was a problem on shady slopes too. On most slopes there isn't enough slab to be an issue, and the slab that does exist is already weakening. You could get minor cracking by stepping above the skin track but no dramatic results in tests.
STABILITY TESTS
 Stability Test Results: 8800', SE: ECTN12 down 25cm on 3/6 FCsf over MFcr. ECTX on top 130cm of snowpack below 3/6 layer
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: Trend:
FILE ATTACHMENTS

190309_strong_midpack_SE_8800.jpg
Very strong snow in the top 140cm of the snowpack. SE, 8800'

190309_frenchmans_wind_NW_NE_9400.jpg
Several wind slabs on NE and NW aspects. The one on the right ran 1000 vertical feet. Crowns are mostly blown in.

190309_frenchmans_wind_NNE_9600.jpg
300 wide, 1 foot deep crown on NNE aspect at 9600

190309_frenchmans_deep_NW_9400.jpg
Possible deep slab - hard to tell if it ran on the basal facets