Pro Field Report

Basic Information

Observation Details

Observation Date:
February 10, 2021
Submitted:
February 10, 2021
Observer:
SAC - Davis, VandenBos
Zone or Region:
Galena Summit and Eastern Mtns
Location:
4th of July Ck (W-N-E, 7,500-8,800')

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
Isolated
One collapse (likely December facets) on the descent.

Snow Stability

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

Media/Attachments

Wind-scouring on Washington Peak in the White Clouds.
This slide likely occurred during the storm in late January. It ran on a W-facing slope at ~9,000' in 4th of July Ck.
This slide likely occurred during the storm in late January. It ran on a wind-loaded N-facing slope at ~9,000' in 4th of July Ck.
This slab avalanche failed on a NW-facing slope around 10,000' on Washington Pk in the White Clouds.
https://www.instagram.com/p/CLIaWujlXzj/

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Wind:
Moderate , N
New/Recent Snowfall:
15-20 cm settled snow since Jan. 27th

Clear and cool for much of the day. Increasing clouds from the NW after noon. Calm at the middle and lower elevations where we were, but there were some plumes in upper elevation terrain of the Sawtooths and Smokys.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Jan 29, 2021
(Estimated) 		4th of July Ck
W 8900ft 		D2 N-Natural
This slide likely occurred during the storm in late January. It ran on a W-facing slope at ~9,000' in 4th of July Ck.
Report
4 Jan 29, 2021
(Estimated) 		4th of July Ck
N 9000ft 		D2 N-Natural
This slide likely occurred during the storm in late January. It ran on a wind-loaded N-facing slope at ~9,000' in 4th of July Ck.
Report
1 Jan 29, 2021
(Estimated) 		4th of July Ck
NW 10000ft 		D2 N-Natural
This slab avalanche failed on a NW-facing slope around 10,000' on Washington Pk in the White Clouds.
Report
4th of July Ck
4th of July Ck
4th of July Ck

We saw no recent avalanches. There were two generations of older avalanches one likely from around Jan 13th and one likely centered around Jan 29th. Ben noted many of the older slides, in an observation from Jan 19th. I've only listed slides that looked more recent than those.

Snowpack Observations

8,500' NE, HS = 110 cm.

The snowpack at lower and middle elevations in 4th of July Creek was shallow and lacked much wind-affect. The snow surface was heavily faceted. Only 15-20 cm of snow sat above the (1/27) interface.

The (12/11) interface was down 70 cm and was just about as dry and weak as I've seen in a pit this season. Snowpack tests were mixed on ECTs but all CPSTs and PSTs failed to end with cut lengths in the mid-20s to near 30.

110-90 F
90-50 4F, FC
50-49 MFcr
49-40 F, FC
40-20 F-, December facets, cupped/chained DH
20-GR 4F-

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
None Specified
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 70 cm
Weak Layer(s): Dec 11, 2020 (FCsf)
Comments: Shaded where observed. From NE at 8,500': ECTP24, ECTN27, ECTX. CPSTs in mid-20s to END. PST 31 and 32/100 END.

With 15-20 cm settled snowfall since (1/27) there wasn't enough snow on this layer for a problem.

Terrain Use

We felt comfortable poking briefly into supported, small avalanche terrain.