Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
February 6, 2021
Submitted:
February 6, 2021
Observer:
SAC - Scott Savage
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Frenchman Ck/Smiley Ck (RECREATIONAL day) (several aspects 7200-9300')

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced
I can't remember the last full day I had with absolutely no collapsing. We avoided steep wind-loaded terrain, but didn't get any cracking on a few small middle elevation wind-loaded ridges/slopes.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Moderate
Stability Trend: 

Bottom Line

Lots of wind-transported snow at upper elevations and the middle-upper elevation transition...but, interestingly, no natural avalanches observed in tha area today. We would not have considered entering wind-loaded upper elevation terrain. Jan 27 weak layer (about 2 feet down) was not showing obvious signs of instability in our travels. The old December facets still look and feel terrible, but they were 3-5' deep above 7600'- trending towards a classic low probability/high consequence deep persistent slab problem in this area.

Media/Attachments

Low resolution photo showing winds pluming snow on multiple ridgelines in the western Smoky Mtns around 2 PM Saturday afternoon.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Temperature:
Teens and 20s F
Wind:
Strong
New/Recent Snowfall:
Flurries noon-2 PM, snowing lightly after that.

Winds were moderate until about noon, bumped up significantly after that. Still some snow available for transport if the winds increase, but running out of ammunition if winds stay as is.

Snowpack Observations

Few observations or tests as this was a day off playing in powder:
7600': HS=125-130cm 1/27=40-45cm below surface (FC, some SH shards)
8500' W/NW: HS=180cm, multiple shear planes at 130, 120, 115 cm but very thin interfaces. I could barely identify 1/27 in this location. 12/11 top at 55cm. ECTX but only isolated upper 90 cm (did not test 12/11 layer). Well graded snowpack F>4F>1F>P above 12/11 (see photo).
8900' N: 1/27 was small FC and SH shards 55cm down from surface, Much lower density snowpack in upper 100cm, HS=180-200cm.

Pit in western Smoky Mtns at 8500' W/NW. HS=180cm, hand hardness shown for upper meter or so after an ECTX test.
Snowpit in western Smoky Mtns near 8500' on W-NW aspect. Total depth=180cm, Dec facets are at 50cm. photo does not show snowpack all the way to the ground.

Avalanche Problems

Obvious wind slab problem at upper elevations and isloated exposed middle elevation terrain.
1/27 weak layer was not as widespread or sensitive here as in other locations I've been in recently.
12/11 is a classic deep persistent slab problem here (still there lurking, probably difficult to trigger).

Terrain Use

We avoided all wind-loaded terrain over 30*, all large avalanche paths (including runout zones), and all slopes with any small portions steeper than about 32-33*. Although the snowpack and stability tests looked better than expected on some aspects, we stayed with our conservative travel plans.