Pro Field Report

Basic Information

Observation Details

Observation Date:
March 17, 2021
Submitted:
March 17, 2021
Observer:
SAC - Ethan Davis
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Morgan Ridge (W-N-E, 6,000-7,800)

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
Isolated
I experienced several collapses, some traveled >100'. They were more interesting than indicative of instability. They occured where the crust at the surface collapsed into moist facets beneath. The largest were on W-facing slopes in thin snow near the ridge and in relatively flat low elevation terrain.

Bottom Line

I avoided sunnier slopes (lack of snow) and did not encounter wet avalanche concerns on more shaded slopes before leaving the field at 2:00 PM. Although hard to trigger, weak layers on shaded, middle elevations remain dry and produced poor snowpack test scores.

Media/Attachments

Weak layers are dormant, but they still exist. Here, a stiff slab rests atop weak, dry facets near the ground. Morgan Ridge E of Sun Valley, N-facing slope at ~7,500'.
Recent looking wet slide near the head of Wilson Ck off of Trail Ck. Upper elevation WNW facing slope.

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Wind:
Moderate , SW

Partly cloudy skies to start with increasing cumulus over the Pios, Boulders and Smokys in the afternoon. A moderate SW wind on ridges kept things feeling relatively cool.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Wilson Ck
W 9500 		D1 WL N-Natural Date unknown, but looked fairly fresh. More of a WNW aspect and it looked to gouge a bit deeper as it curled to the W.
Recent looking wet slide near the head of Wilson Ck off of Trail Ck. Upper elevation WNW facing slope.

I saw numerous older D1-D1.5 wet loose in alpine cirques of the Pioneers. All looked like they occurred last week.

Snowpack Observations

Shadier low elevations:
A stout 20-30 cm crust at the surface this morning was still hanging in there by 2:00 PM. The snowpack was thin, 50-70 cm, and moist/wet beneath the crust to the ground. There were no notable layers where water looked likely to pool. Essentially well-drained moist/wet facets to the ground.

Shadier middle elevations:
Snow depths were 70-100 cm. A variable 10-20 cm weak crust capped a mostly dry, strong midpack. The lower half of the snowpack was a bit weaker leading up to the December facets near the ground. This layer was weak (4F), dry, and produced propagating results.

Last night's lows, as well as today's daytime highs, are both cooler than the previous two days. Unless temps ramp up I don't think enough water is moving through the pack to cause much of a concern on shadier low elevations here.

I didn't observe/travel-on sunnier slopes, they were mostly bare.

Avalanche Problems

I didn't encounter any avalanche problems today. The most likely place to encounter a problem here would have been thin snowpacks on WNW-NW facing slopes at middle and lower elevation in the late-afternoon sun.

Terrain Use

I only closed very steep, soggy slopes. I didn't encounter any. I traveled in steep N-facing terrain.