Professional Observation

Basic Information

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

Recent Avalanches?

Yes

Cracking?

None Experienced

Collapsing?

None Experienced

All roadside glassing and taking photos, so no cracking or collapsing.

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

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.

#	Date	Location	Size	Type	Bed Sfc	Depth	Trigger	Comments	Photo
1	Past 24 hours	Durrance SE 8900	D1.5	SS			N-Natural
5	Past 24 hours	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	Past 24 hours	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	Past 24 hours	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	Today	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	Past 24 hours	Anderson Ck E 9000-9700	D2	SS			N-Natural
3	Past 24 hours	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	Past 24 hours	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	Past 24 hours	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	Past 24 hours	Galena Peak W 10000	D2	SS			N-Natural	D1.5-2, one was larger than the other. Cross-loaded starting zones.	None
1	Past 24 hours	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	Past 24 hours	Salmon River Headwaters NE 9300-9800	D2	SS			N-Natural	N and NE aspects
2	Past 24 hours	Alturas Ck and Beaver Ck NE 9400 and 8800	D2	SS			N-Natural
1	Past 24 hours	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.
1	Past 48 hours	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.
1	Within the past week	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?
1	Today	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.