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PROFESSIONAL OBSERVATION FORM
 Start Date: 03.27.17 Name: Davis Operation: SAC
 Drainage/Route:  McDonald Peak Observed Terrain:  7,000-10,000, S-E-N Zone/Region:  Sawtooth Mountains
WEATHER OBSERVATIONS
 HN24: 5-10 cm HST: 10-20 cm since (3/24) Sky: BKN Precip: S-1 Temps:
 Ridgeline Wind: Light and Intermittent from the W
 Blowing Snow: Snow Available for Transport: Small amounts
 Comments: Overcast skies until about 1100 then broken with scattered snow squalls and sun. Wind never got going up high. Very little snow moving, with 20 cm dry-moist snow available for transport depending on elevation and aspect.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 Comments: No new avalanche observations.
SNOWPACK OBSERVATIONS
 HS: n/o 
 Upper Pack: Sun soaked slopes had baked down to 5-10 cm of moist/wet snow on middle to upper elevation sunny aspects. Shaded slopes held 10-20 cm HST, a little more than half of that was from (3/24-25) capped with a thin MFcr and the the rest fell last night and this morning. Wind slab up to 40 cm thick lee to south wind. 
 Middle Pack: (3/24) MFcr 
 Lower Pack: n/o 
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:
20-40 cm

Likelihood of Triggering
Sensitivity:
Touchy

Spatial Distribution:
Specific
Terrain
  Primary Concern Comments: Small wind slabs on ridges. (photo)
 Comments: Not enough snow for WL to be an issue until upper end of middle or true alpine. Saw some roller balls on alpine souths but no activity.
STABILITY TESTS
 Stability Test Results: Resistant planar hand shears on thin MFcr at (3/24). North-facing, subtly wind-loaded slope at 9,400'.
OBVIOUS SIGNS OF INSTABILITY
 Marked with checkmark if observed:
 Cracking (isolated)   Length: 15'
 Comments: Steep wind-loaded pockets on exposed ridges >9,500'. Loading lee to south wind.
SNOW STABILITY
 Snow Stability Rating for your observed area: Fair Confidence: MODERATE Trend: Improving
 Comments (aspects and elevations of instability, etc): Fair stability and MODERATE in the alpine. Good stability/LOW at middle and very good/LOW at lower.
BOTTOM LINE
 Comments: Only concern today were lingering wind slab that formed (3/24-25). No real evidence that last nights weather did much to change the equation. Sustained moderate wind will still have something to work with as there is at least 20 cm dry snow on upper elevation norths. The slow burn of today's partial sun will put a damper on any WL problems if more sun comes out tomorrow, much of the HST was reduced to 5 cm of moist wet/snow.
FILE ATTACHMENTS

170327_McDonald_cracking_north_9500_ED.JPG
Cracking in wind slab along ridge headed to McDonald Peak.