Pro Field Report

Basic Information

Observation Details

Observation Date:
December 15, 2019
Submitted:
December 15, 2019
Observer:
SAC - Lundy (off duty)
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Avalanche Peak, Camp Creek and north side, 8200-9400', most aspects except E

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
Isolated
Cracking/collapsing was less frequent but still significant. All seem to be on 12/7 surface hoar. On solars, the collapses were smaller. I had a few rumblers on the summit plateau where there was wind-stiffened snow.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
High
Stability Trend: 
Improving

Bottom Line

I found the 12/7 surface hoar everywhere I looked on a variety of aspects at middle and edging into upper elevations (9400' was as high as I got). It seemed the most sensitive on shady slopes and in areas with wind-stiffened snow.

Media/Attachments

Close up of skier-triggered slide on Ego near Galena Summit.

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Wind:
Light , NW

Mostly cloudy in early afternoon, with increasing clouds in the late afternoon. A few snow flurries occurred in late afternoon.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 North side of Avalanche Peak into Rainbow Creek
NW 9200 		D2 SS O-Old Snow 40-50cm N-Natural Approximately 60-70m wide. The depth was about right for the 12/7 SH. Variation in crown depth indicated at least some wind effect.

Snowpack Observations

Snow depth ranged from 40-60cm. Got a significant collapse while skiing on a S aspect at 8600. Cracks propagated out about 20m. See pit below - the fracture occurred on the 12/7 SH atop a MF crust that was buried 30cm deep in this location. The slab was F hard and beginning to facet, so the extent of propagation was quite surprising. I got an ECTP5 in this pit. The 12/7 layer was buried closer to 40cm on shady slopes, and where the wind had stiffened the slab, I got a couple of large, rumbling collapses that shook snow off trees 30m away.

Terrain Use

I avoided avalanche terrain.