Pro Field Report

Basic Information

Observation Details

Observation Date:
April 5, 2023
Submitted:
April 5, 2023
Observer:
SAC - Davis, Genswein
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
McDonald Area (All aspects except W, 7,000'-9,200')

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
Very small sun-induced loose snow avalanches and one fairly fresh looking small wind slab on Prairie Pk.

Snow Stability

Stability Rating: 
Good
Confidence in Rating: 
Moderate
Stability Trend: 
Improving

Bottom Line

We observed unstable snowpack test scores on a sunnier slope with a crust. This crust+facet setup exists in enough places to keep me out of avalanche terrain at or above the middle/upper elevation transition. Sun-induced loose snow avalanches got a little head start today. Many more steep slopes will shed thin layers of recent snow tomorrow.

Media/Attachments

An extended column test (ECT) produced unstable results on this SSE aspect at 9,150' near McDonald Peak in the Sawtooths. The weak layer was a thin layer of facets atop a stout crust (3/19).

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Temperature:
n/o
Wind:
Light , N
New/Recent Snowfall:
HN = 4-12 cm

We enjoyed mostly sunny skies. It felt quite warm. It was mostly calm except for some light N wind above 9,000'. Very light snow flurries did not accumulate. A lot of snow is available for transport with a W or NW wind event. It was cloudier in the W Smokys and near Galena Summit. We observed some snow plumes in the afternoon along the White Clouds and Mushroom Ridge due to NW wind. Snow squalls had deposited up to 2 inches of snow in Ketchum, which appeared to mostly miss Hailey.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Apr 1, 2023
(+/- 3 days) 		Eureka Pk
N 9500ft 		D3 HS-Hard Slab N-Natural
This very large avalanche released on Eureka Pk in the Sawtooths. N aspect at 9,500'.
This very large avalanche released on Eureka Pk in the Sawtooths. N aspect at 9,500'.
This very large avalanche released on Eureka Pk in the Sawtooths. N aspect at 9,500'.
Report
Eureka Pk
 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Prairie Pk
SE 9,300 		D1.5 SS U-Unknown
This small wind slab avalanche released on Prairie Pk in the Smoky Mountains. SE aspect at 9,300'.

Snowpack Observations

ENE @ 8,200' | sheltered, planar slope | HN = 8 cm, HS = 210 cm: (3/19) ECTN26 down 47 cm; (2/18) down 135 cm (not tested), the base of the slab was P+, the weak facets were 4F.

NNW @ 9,100' | sparsely treed slope | HN = 12 cm, HS ~ 200 cm: (3/19) ECTX here and below. Thin layers of near-surface facets appeared well bonded in this pit and other shaded hand pits along the way.

SSE @ 9,150' | sparsely treed slope | HS = 230 cm: (3/19) ECTP11 down 52 cm on 2 mm FC above a 5-8 cm MFcr. The base of the slab graded from F to 1F- at the base.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 45-55 cm
Weak Layer(s): Mar 19, 2023 (FC)
Comments: This problem seems to be hanging on where there is a well developed facet+crust combo. This looks much worse on sunnier slopes. So far the shadier slopes where I've looked are much less concerning.
Deep Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: >100 cm
Weak Layer(s): Feb 18, 2023 (FCsf)
Comments: Not tested. We found notably weaker FC under a stout slab in all locations that we looked.

We did not encounter sensitive wind slabs.

Terrain Use

We avoided avalanche terrain.