Pro Field Report
Basic Information
Observation Details
Observation Date:
November 28, 2022Submitted:
November 28, 2022Observer:
SAC - Chris LundyZone or Region:
Banner SummitLocation:
Copper Mtn (Mostly W thru S. Some N up high.)Signs of Unstable Snow
Recent Avalanches?
YesCracking?
None ExperiencedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
FairConfidence in Rating:
LowStability Trend:
SteadyBottom Line
Very weak snow that formed at the surface during the November dry spell is buried 10" deep. This layer produced several small avalanches with last night's storm and is likely to become a significant player if/when we get more loading later this week.
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
ObscuredTemperature:
teens (estimated)Wind:
Light , NWNew/Recent Snowfall:
15-20cm, 25cm settled HST since 11/22S-1 on and off through the day with ~1cm accumulation. Evidence of moderate drifting from last night's storm in open upper elevation terrain.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| Many |
Stream banks, road cuts, steep slopes at upper elevations. lower to upper |
D1 | SS | 20-25cm | N-Natural | Numerous small avalanches involving the snow since 11/22. Some of these may have failed at the 11/28 interface but most seemed to go on 11/22. I saw small, thin slabs on steep stream banks, road cuts, low elevation sheltered slopes, and upper elevation wind exposed slopes. See photos. Could be an indicator of how touchy this layer will be with additional loading. | None |
Snowpack Observations
HS ranged from 60cm at the highway to 80-100cm at upper elevations. The snowpack at lower elevations was generally full-depth facets. The snowpack gained strength and became more supportable as you gained elevation.
@8200', W: HS 85cm. 11/22 consisted of FCsf and some odd SH that was either rimed or had partially melted. It presented as the classic stripe but I couldn't find clear crystals when I disaggregated it - but rather "popcorn-y" conglomerates. Fairly academic given how weak the FC are too. This layer is buried beneath 25cm of newer snow, ~20cm of which fell overnight. ECTN3,4 on this layer. The October snow was 4F - not particularly weak and produced ECTX x2. See photos.
Based on the above pit and other hand pits, 11/22 is extremely weak and widespread on shady slopes at all elevations. It produced numerous small natural slides on a variety of terrain. The 11/22 layer presents as a fairly stout crust even on lower-angled solar slopes.
I dropped down the lower-angled N facing terrain below the summit (towards the Unknowns) to try to get a look at the October snow on a colder aspect. This area was fairly wind-affected, but on the most sheltered spot I could find the October snow looked similar to the W facing pit - not that weak. This layer could be an issue with a big load, but the 11/22 layer seems far more concerning.
There was minor to moderate drifting in open terrain. Drifts were soft and 20-40cm thick. I poked at the top of some of the steep N side chutes - they didn't seem particularly loaded from last night's storm, but the light was pretty flat.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Layer Depth/Date: 25cm Weak Layer(s): Nov 27, 2022 (FC) Comments: Numerous small naturals observed. Still lacking a widespread slab, but likely to become problematic with future loading. |
Terrain Use
I planned to avoid avalanche terrain due to solo travel and an assessment mindset/low confidence in snowpack assessment.