Pro Field Report
Basic Information
Observation Details
Observation Date:
April 3, 2021Submitted:
April 3, 2021Observer:
SAC - Chris LundyZone or Region:
Banner SummitLocation:
Copper North Side (6700-9000', N-NE & S-SW)Signs of Unstable Snow
Recent Avalanches?
YesCracking?
None ExperiencedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
FairConfidence in Rating:
HighStability Trend:
WorseningBottom Line
A poor refreeze overnight led to wet, mushy snow on most aspects except upper elevation, due north. Wet snow problems worsened in the afternoon as things heated up, but a breeze at middle and upper elevations may have helped keep things cooler than it could have been.
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
Mostly SunnyWind:
Moderate , SWTour was from 1030-1430. Winds were stronger than forecast and blowing a fairly steady moderate at the summit. Light winds were blowing at middle elevations. The wind probably kept things cooler than they would have been.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 4 |
Above Newman Cr, across from Copper N side W 8400 |
D1 | WL | N-Natural | These slides likely involved the recent snow sliding on the 3/18 crust. |
|
A few other very small sluffs were observed in E and NE facing terrain.
Snowpack Observations
Despite above freezing overnight temps, a weak re-freeze occurred producing a crust about 5-7cm thick on upper elevation solars. At 1300 on a SW slope at 8900, this crust was barely ski supportable. You could easily punch a pole through it into bottomless mush (see video). The freeze was better at the valley bottom due to the inversion.
On middle and upper elevation E-NE, the wet problem was primarily moist to wet recent snow sliding on the old 3/18 crust (barely intact/frozen). I tried pushing on a few steep test slopes and couldn't quite get anything to move in the midafternoon - it likely got worse after I left.
I dug on a 7800', NE slope. HS 190cm. The surface consisted of 15cm of wet/saturated snow on a barely frozen 3/18 crust. The top 1m of the snowpack (as deep as I dug) was moist. Interestingly, there was meltwater accumulated in the old 1/27 SH that was buried 90cm down - see photo.
The snowpack and snow surface was dry only on due N aspects above about 8500'
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wet Loose
|
|
Comments: Rose coloring represents expected distribution. Sensitivity may have hit reactive after I left the field. |
Terrain Use
I felt comfortable skiing steep, upper elevation N aspects that were dry. I avoided consequential avalanche terrain where the surface was wet or mushy, which was nearly everywhere.