Pro Field Report

Basic Information

Observation Details

Observation Date:
February 22, 2023
Submitted:
February 22, 2023
Observer:
SAC - Lundy, Davis
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Iron/Goat Divide (6500-9100', SE-E-N-NW)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
None Experienced
Cracks (~6' in length) initiated in facets below a crust. See the avalanches listed below.

Snow Stability

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

Bottom Line

The recent storm dropped 4-6 inches of new snow in this area which did not appreciably change the snow stability on slopes that haven't been wind loaded. In sheltered terrain, we found a variable, messy mix of crusts and facets on sunny aspects and a simpler layer of weak facets on shady slopes. The weakest snow was ~10" down and there currently isn't enough of a slab to be an issue.

While we did not observe a wind slab problem at middle elevations, a number of natural avalanches occurred in wind-loaded, upper elevation and alpine terrain.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Wind:
Light , NW
New/Recent Snowfall:
HN from 2/18 seemed to be 10-15cm at middle elevations

Scattered clouds this morning increased through the day, becoming overcast by afternoon. We had periods of S-1 in the afternoon with only trace accumulation. Cold temps and no solar gain.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Feb 21, 2023
(+/- 1 day) 		Parks Pk
SE 10100ft 		D2.5 N-Natural
These very large avalanches released on E and SE facing slopes of Parks Pk in the Sawtooths. The slides appear to have started as simple wind slabs before stepping down in places to break into more deeply buried weak layers. They ran approximately 1,500 vertical feet.
This very large avalanche released on a SE face of Parks Pk in the Sawtooths. It ran approximately 1,500 vertical feet.
Report
1 Feb 21, 2023
(+/- 1 day) 		Parks Pk
E 10100ft 		D3 N-Natural
This very large avalanche released on an E facing slope of Parks Pk in the Sawtooths. The slide appears to have started as a simple wind slab before stepping down in places to break into more deeply buried weak layers. It ran approximately 1,500 vertical feet.
These very large avalanches released on E and SE facing slopes of Parks Pk in the Sawtooths. The slides appear to have started as simple wind slabs before stepping down in places to break into more deeply buried weak layers. They ran approximately 1,500 vertical feet.
These very large avalanches released on E and SE facing slopes of Parks Pk in the Sawtooths. The slides appear to have started as simple wind slabs before stepping down in places to break into more deeply buried weak layers. They ran approximately 1,500 vertical feet.
Report
1 Feb 21, 2023
(+/- 1 day) 		Decker Pk
E 10100ft 		D2 N-Natural
This large wind slab avalanche released on an E facing slope of Decker Pk at about 10,100'.
Report
1 Feb 21, 2023
(+/- 1 day) 		Merritt Pk
E 9600ft 		D2 SS-Soft Slab N-Natural
This large avalanche released at about 9,600' on an E face of Merritt Pk in the Sawtooths.
Report
1 Feb 21, 2023
(+/- 1 day) 		Merritt Pk
N 10000ft 		D2.5 SS-Soft Slab N-Natural
This very large avalanche released at about 10,000' on a N face of Merritt Pk in the Sawtooths.
This very large avalanche released at about 10,000' on a N face of Merritt Pk in the Sawtooths. This picture shows a portion of the start zone.
This very large avalanche released at about 10,000' on a N face of Merritt Pk in the Sawtooths. This picture shows the lower half of the slide.
Report
Parks Pk
Parks Pk
Decker Pk
Merritt Pk
Merritt Pk

This storm seems to have produced more avalanche activity (in upper elevation, wind loaded terrain) than the last storm. Hard to say why - maybe yesterday's brief periods of intense snowfall coincided with strong NW winds?

Snowpack Observations

Low elevation snowpack consists of 5-7cm of HN on a thin melt-freeze crust over a thick pile of facets.

Above about 8500' we began to see a thin crust at the base of the 2/18 storm. It could have been a rime crust, but felt more like a rain or mist crust. We did not observe it down lower. Perhaps it was from a low, moist cloud that sat on the mountains early in the storm? It was barely perceptible while skiing and felt less pronounced than what Ben observed on Copper on 2/18.

@8500', ESE: HS 150cm. We found variable crust/facets layers in the upper 30cm. In a short span of distance, we went from seeing a crust/facet/crust sandwich to this welded into a single 2-3cm thick crust a few feet away. In either scenario, very weak facets exist below these crusts which produced ECTP17, ECTN14 down 27cm. ECTN3, 9 down 11cm on the rain/rime crust.

@8650, NW: HS 145cm. Sheltered location. Upper snowpack was much simpler, with the 2/13 and 2/18 storms sitting atop a 5cm thick layer of weak facets (down 22cm) - ECTN14, 17. ECTN14x2 on the 2/18 interface down 15cm. Bottom 7-8cm of "slab" is close to 4F but the rest is F.

Avalanche Problems

We did not observe any avalanche problems in the low and mid elevation terrain we traveled through. Although we ascended a wind exposed ridge that is often loaded, the wind slabs we did see were very small and unreactive. Avalanche activity observed in upper elevation/alpine terrain indicates a likely wind slab problem up high.

Terrain Use

In our trip plan, we closed wind loaded terrain steeper than 35 degrees. We felt comfortable skiing sheltered terrain in the mid to upper 30s.