Pro Field Report
Basic Information
Observation Details
Observation Date:
February 5, 2022Submitted:
February 5, 2022Observer:
SAC - VandenBos (off duty)Zone or Region:
Galena Summit and Eastern MtnsLocation:
North Fork Big Wood (6,200-9,600, S-SW-W-NW-N)Signs of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
None ExperiencedAdvanced Information
Weather Summary
Cloud Cover:
Mostly SunnyWind:
Moderate , NWAfternoon wx obs: hands of high clouds did a bit to help limit solar input, but not a ton. Mild temperatures, surfaces were moistening. Gusty NW winds blowing mod to strong along ridgelines, not much snow to transport, but shuffling some loose facets around. T-shirt and alpine short weather in terrain sheltered from the wind.
Avalanche Observations
Appeared to be an older slide (couldn't make out crown but could see debris) at head of Eagle, not sure how old this was. I remember seeing something up there a long ways back (late December?). Could also see crown and debris in "Little Alaska", above Hyndman Creek. Also unsure of timing.
Snowpack Observations
My main objectives were to look at surfaces and check in on 12/11. Significant faceting in the upper snowpack. Good exercise skinning through a sandbox. Lower snowpack is still maintaining some strength, despite the extended drought, even down to the valley bottoms. This seems unique. The slab we rapidly put down in December quickly stiffened to 1F to P and has maintained much of its structure. As stated before, this could make a mighty fine bed surface when it snows again (starting February 25).
I dug for 12/11 at 8,900' on NNW slope, where HS=120-140cm. 12/11 down 90-100cm under a slab that quickly grades to 1F (down~40cm) and then P (down 60-70cm). The most worrisome interface in the October snow facet stack is 2-3cm thick, composed of 4F- crisp, striated DH cups, 3-5mm. Produced ECTP22, ECTX, and ECTP35 (last 15 from the shoulder, no Hulk smashes). Also PST 37/100 END and CPST 43/120 END. It's pretty hard to ignore this snow, but also pretty hard to imagine triggering it without some significant bad luck. The highly variable ECT results are interesting. I've observed these in several locations now.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Weak Layer(s):
Dec 11, 2021 (FC)
Comments: I find it hard to take this off my personal problem list. |
I did not encounter any reactive wind slabs today. I did find a few thin drifts at upper elevations that showed no obvious signs of being unstable. Hard to say how old they were.
Terrain Use
I continue to limit my exposure to slopes holding the 12/11 weak layer (October snow) at the base. This is a tough mental battle, knowing that likelihood of triggering is low. The existence of this weak snow at the base of the snowpack is driving my terrain selection in this zone.