Pro Field Report

Basic Information

Observation Details

Observation Date:
November 29, 2022
Submitted:
November 30, 2022
Observer:
SAC - VandenBos, Davis
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Pole Creek (7,200-10,100', mostly southern half of the compass)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
Isolated

Snow Stability

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

Bottom Line

Sunday and Monday's storm produced natural avalanches in the southern Sawtooths and White Clouds. Avalanches failed in near and above treeline areas where the new snow was stiffened by the wind. Coverage in the White Clouds is remarkably good, even on generally scoured or burned-off W-SW-S facing slopes.

We found very weak snow on all slopes both at the surface and near the ground. This weak snow will not stand up to Wednesday-Thursday's storm snow. We expect widespread avalanching in this area.

Media/Attachments

Several natural avalanches are visible in this photo of Eureka Peak, above the Beaver Creek drainage. The slope pictured faces E/NE and crown elevation ranges from 9,500-10,000'. Based on the appearance of the crowns, these slabs likely failed on the weak snow that developed during the mid-November drought. These avalanches occurred after only 6-8" of snow fell overnight on Sunday and into Monday.
https://youtu.be/1MG2bbqGZzw

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Wind:
Calm
New/Recent Snowfall:
HN: settled 10-12cm at Smiley Creek, 13-15cm as we climbed above Pole Creek

Thin, low, icy clouds hanging over the crest of the Sawtooths for much of the day, periodically moving out the valley and then pulling back. The White Clouds were cloud free for much of the day. Cloud cover increased in the afternoon and low clouds were hanging over most of the mountain ranges (Boulders, Smokys, White Clouds, Sawtooths, Pioneers) by late afternoon.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
3 Nov 28, 2022
(+/- 1 day) 		Eureka Peak
E 10000ft 		D1.5 SS-Soft Slab I-New/Old Interface 1ft N-Natural
Several natural avalanches are visible in this photo of Eureka Peak, above the Beaver Creek drainage. The slope pictured faces E/NE and crown elevation ranges from 9,500-10,000'. Based on the appearance of the crowns, these slabs likely failed on the weak snow that developed during the mid-November drought. These avalanches occurred after only 6-8" of snow fell overnight on Sunday and into Monday.
Report
Eureka Peak

Sunday and Monday's storm produced natural avalanches in the southern Sawtooths and White Clouds. Avalanches failed in near and above treeline areas where the new snow was stiffened by the wind.

Snowpack Observations

Pole Ck, Twin Ck - 8400', W, HS 60cm: (11/27) is buried under 13cm of recent snow. In this location, there was a thin (1cm) crust. (11/1) is down 55 cm. The whole snowpack was very weak. Essentially new snow sitting on a pile of facets bounded on either end by (11/27) and (11/1), which rested on a slick MFcr welded to the ground.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
 Layer Depth/Date: 13cm, (11/27)
Comments: Shaded where I'd expect avalanches following the storm. SW and S aspects may have muted activity where snowpack is thin (lower elevations) or where the crust is thicker and (11/27) was less concerning (middle to upper elevations).
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
 Layer Depth/Date: 55 cm, (11/1)
Weak Layer(s): Nov 1, 2022 (FC)
Comments: Widespread weak snow at the base of the snowpack. I expect that it will be hard to tell the difference between avalanches that fail on (11/27) and (11/1) in this zone.

Terrain Use

We felt comfortable skiing terrain that lacked a cohesive slab of new snow. We avoided stiffer, wind-blown pockets of snow at middle and upper elevations.