Pro Field Report

Basic Information

Observation Details

Observation Date:
March 10, 2023
Submitted:
March 11, 2023
Observer:
SAC - Scott Savage
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
driving and glassing Hailey-Eagle Creek (many lower and middle elevation areas)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
Collapsing and cracking are N/A, roadside observations only

Snow Stability

Stability Rating: 
Very Poor
Confidence in Rating: 
High
Stability Trend: 
Steady

Bottom Line

Today was one of the most widespread avalanche cycles I've ever seen (Wood River Valley - Hailey to Eagle Creek). I saw over 100 natural avalanches, despite the limited visibility for most of the day. Avalanches damaged 2 houses, stuck approximately 10 structures, buried both lanes of HWY75, and blocked the Big Wood River in several places.

Media/Attachments

A natural avalanche released on a lower elevation, west-facing slope and blocked HWY 75 north of Ketchum.
Natural avalanches on SE-E aspects in the Warm Springs Ck drainage.
Natural avalanches on Sun Mountain in the Lake Creek drainage (NW aspects below 7500').
In addition to the wide, obvious crown, you'll see several generations of avalanche crowns and debris in this photo. Many of the SE and NW facing paths in the Eagle Ck headwall released naturally during the March 10 storm.
This relatively small avalanche near Eagle Ck would have been an "ugly ride" if you were caught in it. Unless trees are too dense to ski or ride, the slope can still avalanche.
Natural avalanches in Croy Canyon (NW aspects).

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Temperature:
20s and 30s F
Wind:
Extreme , W
New/Recent Snowfall:
About 1.5" SWE, 12-15" HST

Snowing hard in the morning with rain in Hailey after about 11 AM. Strong S-SE winds until they bumped up to extreme and shifted W after noon. Wind shift/increase coincided with the end of precipitation. Winds were still transporting snow at 4 PM, but not as much as in the noon-3 PM timeframe.

Avalanche Observations

Will add specific avalanche observations and entries over the weekend. The majority of the activity I observed was D2-2.5, NW-N-NE-E-SE aspects, lower and middle elevations, storm slabs and persistent slabs failing on February facets and crust+facet combinations as well as within the low density snow that fell Wed-Thurs.

Snowpack Observations

None performed.

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
 Weak Layer(s): Feb 26, 2023 (FCsf) Feb 18, 2023 (FCsf)
Comments: Shaded area is where I observed the bulk of the persistent slabs that failed. I did not see much upper elevation terrain, but there were D2-D3 slides in the Lake Ck headwall (some of the only upper elevation terrain I observed).
Storm Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 20-40cm
Comments: Widespread small avalanches and cracking, especially this morning. This problem seemed to be fleeting though, decreasing significantly by afternoon. I did not include upper elevations because I observed very little upper elevation terrain.

Terrain Use

I was spooked driving underneath large paths. I watched a small (D1.5-D2) slide release above Penny Lake while I was driving underneath it. I parked in a safe place and watched that area for about 20 minutes before witnessing a significant D2-D2.5 avalanche run full track in that area.