Pro Field Report

Basic Information

Observation Details

Observation Date:
January 2, 2022
Submitted:
January 3, 2022
Observer:
SAC - VandenBos (off duty)
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Trail/Corral Creek (6,000-9,800')

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Snow Stability

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

Bottom Line

Surfaces have weakened thanks to the combination of solar radiation and cold temperatures. I observed two avalanches, a wind slab and a persistent slab.

Media/Attachments

Small surface hoar crystals observed at 6,400' in the Corral Creek drainage.
This persistent slab avalanche was observed above Corral Creek, near Johnstone Peak. It failed on a N/NW facing slope at 8,600'. Based on the appearance of the crown it failed on layer of weak snow (persistent slab). The terrain and trees below the crown limited its size, but the crown is over 500' wide.
Debris and mostly obscured crown from a fesh wind slab (?) visible along the Lake Creek headwall. The slide started around 10,000' on a S/SE facing slope.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Wind:
Light , NW

Winds blowing light out of the S/SW, increasing to mod in the afternoon. Skies stayed mostly cloudy to overcast all day, limiting direct input of direct solar radiation. A deep temperature inversion was in place in the morning. This mixed out partially but not completely.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Dec 29, 2021
(+/- 3 days) 		Morgan Ridge
N 8600ft 		D1.5 SS-Soft Slab N-Natural
This persistent slab avalanche was observed above Corral Creek, near Johnstone Peak. It failed on a N/NW facing slope at 8,600'. Based on the appearance of the crown it failed on layer of weak snow (persistent slab). The terrain and trees below the crown limited its size, but the crown is over 500' wide.
Report
Morgan Ridge

In addition to the above reported persistent slab I observed a recent wind (?) slab that failed on the Lake Creek headwall. I did not have a great perspective on this slab so its pretty tough to say more about it.

Snowpack Observations

Out for a surface inventory. I observed widespread faceting of the current snow surface as well as a widespread layer of small surface hoar at the snow surface. A few quick pits revealed a mix of buried FCsf, and FCsf+MFcr combos down 40-50cm near interface between two main storm events.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Weak Layer(s): Dec 11, 2021 (FC)
Wind Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5

Most of the terrain I traveled through held neither of these problems.

Terrain Use

Felt comfortable entering avalanche terrain that did not have significant amounts of remnant October snow and that had did not harbor wind slabs over midpack weak layers.