Professional Observation
Basic Information
Observation Details
Observation Date:
January 1, 2020Submitted:
January 2, 2020Observer:
SAC - SavageZone or Region:
Galena Summit and Eastern MtnsLocation:
Titus Ridge to 9400', eastern side of the ridgeSigns of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
PoorConfidence in Rating:
HighStability Trend:
Bottom Line
Lots of evidence of instability on SE aspects: significant natural slide in headwaters of Eagle Creek, small pockets that slid observed on the drive up to Galena Summit, a soft, shallow (6-12" thick) but wide (400 ft) natural or remote triggered slide at the top of the pass, cracking in very soft slabs at ridgeline, and poor stability test scores on our old buried surface hoar layer. Add the strong winds with lots of wind loading in other places - especially upper elevations - and you have a bad setup.
Advanced Information
Weather Summary
Cloud Cover:
ObscuredTemperature:
20FWind:
Moderate , NW12-20cm (5-8") of new storm snow by dark. Snowing S-1 to S3 while I was out for 90 minutes (4 PM until dark). There was snow on tree limbs from the pass to the top of the first bump at about 9600', but I could hear the wind cranking at higher elevations. There was a lot of snow available for transport.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Today |
Eagle Creek headwaters SE alpine |
D2 | U | N-Natural | Terrible vis for viewing avalanche activity when I was driving up to the pass around 3 PM, but there was a donut hole around Eagle Creek. I saw one obvious debris pile in the headwaters area, at least a D2. | None | ||
| 1 | Today |
Galena Summit ("Verlons") SE 8900 |
D1.5 | SS | I-New/Old Interface | 25cm (10") | U-Unknown | Slide occurred between 4-4:30PM while I was on Titus Ridge. It was either remotely ski triggered from hundreds of feet above on the flat ridge or a natural. The plow did not trigger it (conversation with plow driver). Instagram video link https://www.instagram.com/p/B60onF2gAH4/ |
|
Touchy new snow interface on middle elevation SE aspects. I also saw a small road cut a half mile before the top of the pass that had released naturally, also less than a foot thick.
Snowpack Observations
9100' SE aspect: 80cm depth. 18cm new snow, 12/11 crust+FC at 44cm, 12/7 SH at 15cm. ECTN18 on 12/7 SH at 15cm. PST22/100end, SP, on 12/7 at 15cm. CPST25/100end, SP, on 12/7 at 15 cm.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Layer Depth/Date: 12/31 interface of FC+crust 20cm down, also 12/7 SH down 65cm (2 feet) The 12/31 interface is quite touchy but slides will be small. The 12/7 layer is still showing poor test scores but has been very stubborn leading up to this storm. |
Only observed a limited wedge of middle elevation terrain in short 1hr walk.
Terrain Use
All avalanche terrain was off-limits. Quick solo tour out the ridge just before dark.
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