Pro Field Report
Basic Information
Observation Details
Observation Date:
January 29, 2021Submitted:
January 29, 2021Observer:
SAC - Chris Lundy (off duty)Zone or Region:
Banner SummitLocation:
Bull Trout (7000-8000, primarily E)Signs of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
IsolatedSnow Stability
Stability Rating:
FairConfidence in Rating:
ModerateStability Trend:
SteadyBottom Line
16" of recent storm snow is sitting atop weak old snow surfaces, including surface hoar. You could likely trigger a slide on slopes over about 38* degrees and on steep, convex rolls. The December facet layer is buried around 4' deep, but is showing little to no sign of strengthening.
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
ObscuredTemperature:
increasingWind:
CalmNew/Recent Snowfall:
40cm settled HST, 5-7cm HN from 1100-1600S1 most of the day, with periods of S2. Increasing temps led to soggy conditions at lower elevations (at least clothing-wise, snow stayed dry).
Avalanche Observations
Terrible visibility
Snowpack Observations
HS around 160-170cm in the terrain we traveled through, with the top 40cm since 1/26.
@7300, E: This was below rain line. FC above and below rain crust, but ECTX in top 60cm of snowpack.
@8000, E: HS 165cm. SH and FCsf found beneath 40cm HST. ECTP11. 12/11 FC 130cm down - still 4F and showing little signs of change. See photo and video.
Unsure of distribution of SH but it was found in several hand pits at mid elevations. Does not seem to be enough load on it for now, although I suspect you could have triggered a small slide on something over 38*.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Storm Slab
|
|
Unknown |
Layer Depth/Date: 40cm - 1/26 interface Comments: ECTP11 where 1/26 = SH. Rose indicates observed terrain. |
||
Deep Persistent Slab
|
|
Layer Depth/Date: 120-130cm Weak Layer(s): Nov 7, 2020 (DH) Comments: Rose indicates observed terrain. Sensitivity based purely on depth. |
We did not get into wind-exposed, upper elevation terrain.
Terrain Use
We traveled on small slopes around 30 degrees but otherwise avoided avalanche terrain.