Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
March 9, 2020
Submitted:
March 9, 2020
Observer:
SAC - Stefan, Coba
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Abe's Armchair

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
None Experienced
Cracking isolated to wind loaded upper elevs, mostly just below ridgeline but also some cross loaded features. Cracks mostly in the 3-6' range 4-8" deep, we did manage to push some very small slabs, 4-6" thick 3-6' square.

Snow Stability

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

Bottom Line

We found very isolated wind slabs directly below ridgeline, 4-8" thick. Snow stayed cool all day at upper elevation, but took ambient heat at low elevs and crust broke down.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Wind:
Light , SW

Light snow showers and cloudy in the morning, breaking towards midday. HN around 1", plus around 3" from Sunday.
N Sawtooth beyond Alturas still completely socked in when we exited the field around 3pm. Snow cool in the morning, taking heat in the afternoon at lower elevs where crust broke down. Mid elev solars got a little bit sticky from radiation.
Light wind, no transport to speak of.

Avalanche Observations

Saw a couple of old D1-D1.5 loose wet from before the weekend on mid elevation W facing steep terrain, no new activity.

Snowpack Observations

Low elevation sheltered, flat treed terrain still faceted to ground under a 2-5cm MFcr, solars had 10-15cm MFcr in the morning with 10-15cm of moist snow below. HS around 60cm around 7300'.

HN approx 3cm + 7cm from Sunday still well preserved on sheltered terrain. On solars this rests on a mostly supportive MFcf, on shadies it's a mixed bag of old weathered snow, slick windbuff or stack of facets, sometimes under thin crusts.
Mid elevation shadies are faceted to gnd.
On mid elev. solars there is around 20cm F hard FCsf sandwitched between the MFcr and the 1F slab below. Basal facets moist close to gnd and nonreactive to ECT and DT.

At ridgeline level we found isolated reactive windslabs up to 30cm thick, but mostly in the 10-20cm range and quite small, typically 1m^2 or less.
Dropping just 30m or so leeward from ridgetop and snow is more or less unconsolidated and unreactive.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
Layer Depth/Date: 10-30cm, 3/7
Comments: Distribution confined to immediately below ridgetop

Terrain Use

We avoided wind loaded avalanche terrain.