Professional Field Report
Basic Information
Observation Details
Observation Date:
March 9, 2020Submitted:
March 9, 2020Observer:
SAC - Stefan, CobaZone or Region:
Sawtooth and Western Smoky MtnsLocation:
Abe's ArmchairSigns of Unstable Snow
Recent Avalanches?
None ObservedCracking?
IsolatedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
GoodConfidence in Rating:
HighStability Trend:
SteadyBottom 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 CloudyWind:
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
|
|
Layer Depth/Date: 10-30cm, 3/7 Comments: Distribution confined to immediately below ridgetop |
Terrain Use
We avoided wind loaded avalanche terrain.