Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
March 25, 2023
Submitted:
March 26, 2023
Observer:
SAC - VandenBos (off duty)
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Fishhook (6,500-9,300')

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
None Experienced
I experienced cracking involving the new snow since 3/23 in wind-loaded/stiffened areas where the new snow sat on crusts with facets (SE-S). Cracks extended up to 10m in places. This set up will be worrying with additional loading.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Low
Stability Trend: 

Advanced Information

Weather Summary

Cloud Cover:
Overcast
New/Recent Snowfall:
About 20-25cm of new snow has accumulated deeper in the range here since 3/23, more like 10cm on the moraine on the approach.

Skies were mostly cloudy to overcast all day, with periods of diffuse sunshine from time to time. Snow showers started in the early afternoon and continued on and off until the end of my tour. Winds were light at lower and middle elevations, it sounded and looked like they were blowing harder on ridgelines.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Mar 10, 2023
(+/- 3 days)
Fishhook drainage
SE 9000ft
D3 HS-Hard Slab N-Natural Report
1 Mar 14, 2023
(+/- 1 day)
Fishhook drainage
SE 8800ft
D3.5 HS-Hard Slab N-Natural Report
1 Mar 10, 2023
(+/- 3 days)
Fishhook drainage
S 9800ft
D3 HS-Hard Slab N-Natural Report
1 Mar 14, 2023
(+/- 3 days)
Fishhook drainage
SE 9300ft
D3 HS-Hard Slab N-Natural Report
Fishhook drainage
Fishhook drainage
Fishhook drainage
Fishhook drainage

My visibility was poor and I could only really see the terrain immediately around me. I found at least 5 D3s in a relatively small area, mostly relying on debris to identify these as many crowns have been filled back in. The debris looked like it came in two rounds, likely from the two big storm pulses in March.

Snowpack Observations

Mostly just moving through terrain and looking around. I found wind-stiffened/drifted snow down to about 8400 ', with most terrain below this holding unaffected snow. About 20-25cm of new snow has accumulated deeper in the range here since 3/23, more like 10cm on the moraine on the approach. Solars and solar margins hold a variety of crusts in the upper snowpack, with the character depending on aspect, elevation, and slope angle. I experienced cracking involving the uppermost crust on a S facing slope at 9,000'. Cracks extended as far as 10m. With more snow and/or wind loading this combination would produce avalanches. I suspect it will be hard to figure out exactly which slopes are harboring reactive crust+facet combos, but feel confident that they are out there.

Avalanche Problems

Deeply buried weak layer continues to drive my decision making. Sensitive wind drifts kept me out of steeper terrain where I suspected 2/18 wasn't as concerning. It feels like we may be developing a persistent slab problem at 3/19 and/or 3/23 interfaces

Terrain Use

Went out trying to convince myself to enter more avalanche terrain than I have in recent days. I couldn't convince myself this was a good idea and I traveled pretty conservatively.