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PROFESSIONAL OBSERVATION FORM
 Start Date: 02.23.18 Name: VandenBos, Wieland Operation: SAC
 Drainage/Route:  Peak 2 (Ben), N/S Fork Soldier Ck (Matt) Observed Terrain:  5600-9600 Zone/Region:  Soldier Mountains
WEATHER OBSERVATIONS
 HN24: HST: 15-60cm Sky: CLR Precip: Temps:
 Ridgeline Wind: Light from the NW
 Blowing Snow: Prev Snow Available for Transport: Large amounts
 Comments: Calm to light winds, 100% solar day with building cumulus humilis clouds visible over Pioneers and WRV mountains. Ben: measured density of upper ~1' of snow at a consistent 4.5%, maybe even a touch lighter (after nearly 24 hours of settlement...).
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 1 Wash Canyon 1.5 U E 7700 Snowmobile track nearby but don't think it was the trigger, might have been though.
 1 S. Fork Soldier 1 U NE 8700 Likely snowmobile triggered. Failed on FC above crust.
 1 Salt Bowns 1 NE 7200 Wasn't there on the way in, likely sled triggered by others after us.
 1 Buttercup 1.5 N W 8600 Midslope crown. Likely persistent.
SNOWPACK OBSERVATIONS
 HS: 20-160cm 
 Upper Pack: 15-60cm HST resting on thin layer of FC  
 Middle Pack: Highly variable depending on aspect/elev/latitude. Tough to nail down anything consistent. 
 Lower Pack: Found 12/2 down 105cm @ 8000' with 12/19 FCxr fairly strong. 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:
20-100cm

Likelihood of Triggering
Sensitivity:
Stubborn

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

Layer/Depth:
2/14

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Widespread
Terrain
  Problem 2 Comments: 
STABILITY TESTS
 Stability Test Results: ECTN down 50cm on 2/14 FC on S @ 7600 and ECTP14 x2 on 2/14 FC on NE at same elevation.
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Cracking (isolated)    
 Comments: Cracking in freshly deposited wind drifts. Drifts were isolated and very soft, but could become a much more significant problem with additional wind.
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: Trend:
BOTTOM LINE
 Comments: Ben (cat ski terrain): a bit surprised by lack of natural activity, given rate and amount of loading and poor structure. Lack of winds certainly helped things to behave but looking forward, there are huge amounts of SAFT and a few weak layers to choose from. Even though yesterday's storm didn't produce much natural activity I'd be expecting to see more activity in this areas as winds increase (its already been blowing steady for 4 hours as of 9:00pm) and additional snow falls. Cold, calm air and intense solar radiation allowed for radiation recrystallization to occur on the southern half of the compass.

Matt: Not a typical soldiers day with little previous wind after a large dump. Fresh and older wind slab over FC was culprit of the (likely) snowmobile triggered slide. HST amounts varied quite a bit as you moved away from that bullseye of the lower soldier wx station area. Smoky Dome canyon and north did not look to have received as much snow, nor did areas near Elk Ridge. Prestorm HS increased as one headed north in latitude. Surprised at how good the riding was above 7000' on all aspects. Still need to watch for thin areas. Also observed radiation recrystallization at days end on S/SE mixed in with some overnight FC/SH growth. A few different buried FC and crust layers along with new surface FC that should produce slides with more loading.
FILE ATTACHMENTS

SForkSoldier.jpg

WashCanyon.jpg