Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
January 8, 2021
Submitted:
January 8, 2021
Observer:
Lundy, Davis, Daly
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
Baldy OB/Bassett Gulch (8400-8900, W-N (variety of aspects/elevations in bounds))

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
Isolated
Several small collapses/cracks (15-30' radius) on a slope with a slightly wind-stiffened slab.

Snow Stability

Stability Rating: 
Good
Confidence in Rating: 
Moderate
Stability Trend: 
Improving

Bottom Line

Snowpack in the Baldy OB is thin and very weak. Outside of wind-affected areas, the slab seems too thin and soft to cause widespread instability. It doesn't take much effect from the wind to provide a stiff enough slab to produce collapsing/cracking and poor snowpack test scores.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Wind:
Light
New/Recent Snowfall:
A few cm's

Top of Baldy was in and out of the clouds.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Jan 5, 2021
(+/- 1 day)
Bassett Gulch
N 7700ft
D2 SS-Soft Slab O-Old Snow N-Natural
Report
Bassett Gulch

Snowpack Observations

Snowpack is very thin and weak and there is only reasonable coverage on mid to upper elevation shaded slopes. December weak layer presents as well developed depth hoar in places and is uniformly F- in hardness. 11/17 dirty crust is almost completely eaten away, and solstice crust is also quite deteriorated. On middle and upper elevation shaded aspects, the slab is 25-30cm thick and F to F+ in hardness - generally insufficient to produce instability. But it takes very little wind-stiffening to change the equation.

Big North, 8500', N: HS 60cm. 12/11 FC/DH down 30cm - ECTX, PST25/100end. Slab was barely F+ over F- weak layer. We had a collapse near the pit site where the slab was slightly wind-stiffened.

Top of Bassett, 8900', WNW: HS 50cm. Slab was just slightly stiffer from wind (4F-) but still 30cm thick - this was enough to produce ECTP14, PST29/100end.

ECTP14 down 30cm at the top of Bassett, 8900', WNW

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
Layer Depth/Date: 30cm
Weak Layer(s): Dec 11, 2020 (FCsf)
Comments: Problem is more reactive where there is wind-stiffening of the slab.

Terrain Use

We avoided consequential avalanche terrain.