Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
March 20, 2021
Submitted:
March 20, 2021
Observer:
SAC - Chris Lundy
Zone or Region:
Banner Summit
Location:
Cape Horn Ridge (6700-8900', NE-E-SE-S)

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced

Snow Stability

Stability Rating: 
Good
Confidence in Rating: 
High
Stability Trend: 
Steady

Bottom Line

Since yesterday morning, 8-10" of new snow fell at upper elevations on Banner Summit. Primary avalanche concern today was wet snow at low elevations. At middle and upper elevations, the snow stayed cold enough to prevent wet snow problems. I did not observe significant wind loading along upper elevation ridgelines.

Media/Attachments

https://youtu.be/M7vubZDUJaw

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Wind:
Light , NW
New/Recent Snowfall:
5cm of lower density HN fell early this morning. 15cm of moist to wet total HST at the HWY, 20-23cm dry HST on upper elevation shady slopes.

More sunshine than expected this morning, but clouds increased around noon and snow squall brought S2 for a brief period. No wind loading was occurring while I was out, and loading yesterday was less than forecast.

Avalanche Observations

Did not observe any significant avalanche activity. Glassing the northern Sawtooths and the mountains south of Copper this morning in good light, I only saw minor D1 dry loose sluffing on very steep, rocky slopes that occurred near the end of the storm.

Snowpack Observations

At the highway level, yesterday's 10cm HN was wet enough that it was just barely ski supportable this morning and was covered with the 5cm of HN from early today. The HST increased and dried out with elevation, with up to 23cm of dry HST observed on upper elevation shadies. At mid to upper elevations, the old 3/18 surface crust stayed frozen and supportable today. Lower elevations became moist to wet and the 3/18 crust thawed - at 2pm conditions were not quite wet enough to trigger wet slides, but it might have got there later in the afternoon.

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: I expect that the wet problem existed on all aspects at lower elevations by the afternoon.

Drifting along exposed ridges was minimal and I did not observe any wind slabs.

Terrain Use

Terrain use was more dictated by solo travel than conditions.