Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
April 3, 2021
Submitted:
April 3, 2021
Observer:
Chris Lundy
Zone or Region:
Banner Summit
Location:
Copper North Side (6700-9000', N-NE & S-SW)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
I observed a few small wet loose avalanches.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
High
Stability Trend: 
Worsening

Bottom 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

Recent wet slides across from Copper. 8400', W.
Meltwater accumulating in old layer of surface hoar that was buried in late-January. This layer was buried 3' deep on a NE aspect at 7800' on Copper Mtn.
A ski-induced pinwheel in middle elevation terrain on Copper Mtn.
https://www.instagram.com/p/CNOA1pCFHEq/

Advanced Information

Weather Summary

Cloud Cover:
Mostly Sunny
Wind:
Moderate , SW

Tour 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.
Recent wet slides across from Copper. 8400', W.

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'

Meltwater accumulating in old layer of surface hoar that was buried in late-January. This layer was buried 3' deep on a NE aspect at 7800' on Copper Mtn.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wet Loose
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
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.