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Professional Observation

Basic Information

Observation Details

Observation Date:
January 14, 2020
Submitted:
January 14, 2020
Observer:
SAC - Savage
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
Wells Summit - Wardrop Ck, Basalt Ck: 5450-7200', many aspects

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
None Experienced
One significant slide observed, see below. Isolated cracks shooting from sled skis in stiff drifts on side of road. No collapsing noted but I was only on a sled with a helmet on and probably would not have heard any collapsing.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Moderate
Stability Trend: 

Bottom Line

Quick trip in middle and lower elevation terrain. Lower elevations: slopes without recent wind-loading are notably more stable than wind-loaded slopes - stay off the wind drifts and your chances of triggering slides go way down. Middle elevations: more snow + more wind + more persistent weak layers (facets and/or crusts in the lower and middle of the snowpack) + more recent avalanche activity = sketchy conditions.

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Temperature:
15-22F
Wind:
Light , W

There was about 18" of snow on the Wells Summit road (since Sunday afternoon). There was about 2 feet of settled storm snow around 6500-7000' in sheltered terrain. Skies ranged from partly cloudy (driving from Hailey to Fairfield early afternoon) to overcast (trailhead) to obscured and snowing while out from 3-5 PM. Snow started light, was S3 (1 inch/hr) while I was out and for much of the drive back to Hailey. Winds were moving snow on the peaks west of Hailey/Bellevue on the way over and in the valleys over to Fairfield. Winds were light around Wells Summit.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Past 48 hours Wells Summit area - Wardrop Ck
N 7400' 		D2 U U-Unknown The slide was blown in a bit, guessing it occurred during the heavy snowfall and wind event Sunday night/early Monday morning but could have been human triggered on Monday? The crown looked like a persistent slab failing in a wind-loaded area.
D2, N aspect near 7400' at Wells Summit, unknown trigger.

Snowpack Observations

Total depth = 70-110cm below 6500 ft, 100-140cm at 6500-7200 ft. About 2 feet settled storm snow, no clue how much in the past 12-24 hours. There were sporadic 3-4 ft drifts on and near the road above about 6500 ft. The extent of wind-loading was similar or less than in Croy Canyon near Rotarun (see Observation from yesterday).
W/SW ~7050 ft: HS=125cm. Mix of F/4F PP with some 1F wind particles in the newer/storm snow. 12/31 layer was 2 crusts with FC above and below from 55-58cm (about 2 feet down). Mixed forms (not terrible looking) from 30-60cm with thin FC layer (12/7?) at 38cm. FC from 30cm to G with some larger DH grains at the bottom, but moist. Notable results = ECTP16, SP/Q1, @58cm on very thin layer of FC above the upper crust and PST31/100end, SP/Q1 same layer. A couple ECTN easy, dirty shears, on mid-storm layers/interfaces in the newer snow and a hard, dirty ECTN in the DH about 25cm above the ground.

Structure in pit, following ECT test.
Same pit with slab displaced to show failure layer on small facets above upper crust.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 30-120cm (1-4')
Unknown sensitivity, but leaning towards reactive or stubborn. Terrain in this area leads to swirling winds and loading on many aspects.
Persistent Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 30-80cm (1-2.5')
Probably more of a problem where recently wind-loaded, but the crust+facet complex on some sunny aspects would have me nervous even in sheltered terrain.

Terrain Use

I stayed out of avalanche terrain. I was on a solo mission.

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