Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
April 1, 2020
Submitted:
April 1, 2020
Observer:
SAC - Savage
Zone or Region:
Galena Summit and Eastern Mtns
Location:
glassing Hailey to Smiley Creek

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
All roadside glassing and taking photos, so no cracking or collapsing.

Bottom Line

As expected following a big storm and the earthquake, I saw a lot of natural avalanche activity. While most of the avalanches appeared to be "fresh" with little snow covering the debris or crowns, it's impossible to tell whether many of the slides failed before, during, or after the earthquake. That being said, there were some odd patterns of natural activity: observed activity involved middle elevation terrain and the middle/upper elevation transition as much or more than alpine terrain, paths that don't run that frequently ran, and most of the slides appeared to involve the new snow or weak layers buried not very far beneath the new snow. The "unusual" nature of this avalanche cycle leads me to believe many of the slides were triggered by the earthquake. My observations are almost entirely in the Smoky Mtns, and few avalanches were observed in the Boulder Mtns. This may be due to less storm snow in the Boulders, or it could be a function of looking at the west side of the range and not seeing many of the eastern aspects. The most likely explanation is a mixture of both. I lost visibility when I got to Smiley Creek and could only see the "front range" from the Frenchman Ck drainage north. We will post a separate observation for the widespread, impressive northern Sawtooths activity.

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Temperature:
20s F
Wind:
Light

Partly cloudy from Ketchum to Smiley Creek. Obscured from Smiley Creek north on the Sawtooths side of the road, partly to mostly cloudy on the White Clouds side.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Durrance
SE 8900
D1.5 SS N-Natural
5 Goat Ck
SE 9400-10000
D2 SS N-Natural E, SE, and S aspects. Several soft slabs, some loose snow, and some mixed. Some may be D2.5.
1 N Fork Wood River
W alpine
D2 U N-Natural Could not see crown or where slide originated, just the track. Occurred in wind-affected terrain, so I'd guess a slab was involved. None
1 Newman Ck (Baker)
NE 9500
D2 SS N-Natural Also saw a D2 mix of loose+SS coming out of the rocks in the next cirque to the north.
4 Silver Lake cirque and Boulder Peak
S alpine
D1 WL N-Natural Some small D1-1.5 dribbles on solar slopes in this area. None
5 Anderson Ck
E 9000-9700
D2 SS N-Natural
(4-1-2020) These slab avalanches release naturally on E aspects near and above 9000' in the Anderson Creek drainage on Tuesday, 3-31.
3 Prairie Ck
E 9600
D2 SS N-Natural E-SE aspects, wide slabs triggered by sluffs in most cases. Maybe 2.5 for the biggest one?
2 W Fork Prairie Ck
E alpine
D2.5 SS N-Natural One D2, one borderline D2.5-3 over 500 ft wide. E and SE aspects.
8-10 Owl Ck - Saviers Peak and Bromaghin area
E alpine
D2 SS N-Natural E, SE, and NE aspects. Occurred throughout the storm with some obscured crowns/debris, some partially blown in, and some fresh. Some may be D2.5, hard to tell.
2 Galena Peak
W 10000
D2 SS N-Natural D1.5-2, one was larger than the other. Cross-loaded starting zones. None
1 Titus Lake (peak above the lake)
E 9600
D1.5 SS U-Unknown May have been remotely triggered today by skiers who skied the Titus Lake Chutes just uphill of this crown, unknown trigger. Slide could have been D1.5 or D2, could only see the crown.
3 Salmon River Headwaters
NE 9300-9800
D2 SS N-Natural N and NE aspects
2 Alturas Ck and Beaver Ck
NE 9400 and 8800
D2 SS N-Natural
1 Bromaghin Peak
NE 9000-9700
D3.5 U N-Natural Some thicker, wind-blown parts of the crown look like they are in the 4-7' range.
(4-01-20) Large natural avalanche on a NE facing slope on Bromaghin Peak in the Smoky Mtns. This avalanche is about 2000' wide.
1 Guyer Hot Springs - Warm Springs Ck
NE 6100
D2 WL G-Ground 1-2 feet N-Natural Gouging wet loose avalanche that was witnessed during the earthquake at 6 PM on Tuesday, March 31. It crossed the river, took out a few trees. Andrew Dunning photo.
(3-31-2020) This wet loose avalanche on a shady slope in the Warm Springs Ck drainage naturally released near the Greyhawk parking lot just after the earthquake. (A. Dunning photo)
1 Big North - Warm Springs Ck
NW 7000
D2 WL O-Old Snow N-Natural Mostly surficial wet loose slide that released on 3/30. 3rd hand report says it happened while it may have been raining at that elevation?
Warm Springs Big North
1 Avalanche Peak
E 9300
D2 SS 18" AS-Skier
r-Remote
E-NE aspect. Reliable 3rd hand report of remote skier triggered slide, intentional. Chris Marshall (off duty ski guide) talked to the reporting party and provided the photo.
(4/1/20) Avalanche Peak near Galena Summit, ENE aspect near 9300'. This slide was remotely triggered by skiers who expected the slope to be unstable. (Photo: Chris Marshall)