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PROFESSIONAL OBSERVATION FORM
 Start Date: 02.09.19 Name: Lundy Operation: SAC
 Drainage/Route:  Bench Lakes Observed Terrain:  6600-8700' Zone/Region:  Sawtooth Mountains
WEATHER OBSERVATIONS
 HN24: 2cm HST: 3cm Sky: X Precip: S-1 Temps:
 Ridgeline Wind:
 Blowing Snow: L Snow Available for Transport: Large amounts
 Comments: A bit less new snow than the WR Valley :-) 1cm new at the start of the day and another 1cm during the day. Didn't get up onto any upper elevation ridges, but there was some wind transport on the approach trail moraine. Winds were calm to light at the upper Bench Lake.
AVALANCHE OBSERVATIONS
None Reported
 Comments: Groups had skied 40+ degree, rocky, north-facing terrain above the 4th lake with no results. Looks like folks had skied above 5th lake but the visibility was limited to see how high they went.
SNOWPACK OBSERVATIONS
 HS: 120-150cm at mid elevations. 150-200cm on the lower end of upper elevation. 
 Upper Pack: 30-35cm recent HST Thin layer of FCsf below that on shady slopes/MFcr on solars 
 Middle Pack: 1F to P RG 
 Lower Pack: Basal FC are 1F where deep (say over 150cm) ranging to F in shallow, weak areas where HS <100cm. 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Deep Persistent Slab

Layer/Depth:
Basal/100-150cm

Likelihood of Triggering
Sensitivity:
Unreactive

Spatial Distribution:
Widespread
Terrain
  Primary Concern Comments: 
 Comments: Presume wind slab problem at upper elevations but no direct observations other than light wind transport at low elevations.
STABILITY TESTS
 Stability Test Results: I dug at the 5th lake looking to get some info on the deep slab problem. Average HS in this area was 150-200cm. I purposely dug in a shallower area, and ended up with a boulder on the side of my pit. The depth ranged from 85cm over the boulder to 135cm (see photo). Even the deep end was shallower than average for this area. I performed an ECT and Cross slope PST across the variable depth. I tapped and cut from the shallow side towards the deeper end, thinking that may simulate triggering from a shallow spot. I received an ECTX even with hitting as hard as I could. I stomped on the shovel and got the block to propagate. The xslope PST was 50/120end but not very dramatic.
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: Trend:
FILE ATTACHMENTS

190209_bench_lakes_pit labeled.jpeg
Configuration of snowpack in weak area ECT