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Professional Observation

Basic Information

Observation Details

Observation Date:
March 18, 2020
Submitted:
March 18, 2020
Observer:
SAC - Savage
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Baker Ck/Brodie Gulch: 6650-9300', most aspects

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced
We saw a fair amount of terrain and didn't see any natural avalanche activity.

Snow Stability

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

Bottom Line

The recent storm (about 4-8" of new snow at middle and upper elevations near Baker Lake) is tipping us away from the simple "what you see is what you get" scenario and moving towards a persistent slab problem in specific places - the weak facets that formed in February and early March are 12-18" below the surface in places and need to be considered. Where we traveled today, I was leery of slopes steeper than about 35 degrees that had stiff, wind-transported snow since March 7th. I found this snowpack setup at and immediately below exposed ridgelines over 9000' on E-NE-N-NW aspects where I traveled. More southerly aspects had a very hard crust below the new snow and were still managed by the "what you see is what you get" mindset. With full sun expected tomorrow and Friday, the southerly aspects will probably have wet loose issues.

Media

(3-18-20) Snowpit profile in Brodie Gulch just below ridge, 9250', on somewhat sheltered N aspect.
(3-18-20) Snowpit profile in Brodie Gulch on

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Temperature:
20s F (above 8000')
Wind:
Light , SW

2" new snow at Baker Ck parking lot, about 6" new snow at summer trailhead/bathroom by Baker Lake, 8" near the ridge between Baker Ck and Brodie Gulch. Variable cloud cover ranging from overcast to partly cloudy. Winds were gusting to moderate and moving a tiny amount of snow today. W-S-E aspects below 9300' were affected by solar radiation/heat; on these slopes, winds will need to increase significantly to transport snow.

Snowpack Observations

W-SE-S-SE aspects: the new snow was moist by 3 PM and will have a crust tomorrow. On these solar aspects, there was a substantial knife-hard crust below the new snow above about 8200'. Below 8200', the crust wasn't as hard and will become unsupportable more quickly in the coming days.
Steeper shady aspects stayed dry. Heavily wind-loaded pit/stability test location on NE aspect at ridgeline was concerning (see photos below and profile above).

(3-18-20) Unstable stability test result on NE aspect near 9200'. This location was in a heavily wind-loaded area at an exposed ridgeline, and the wind-effect diminished quickly as you moved a little bit below the ridge.
(3-18-20) Snowpit on a wind-loaded ridgeline.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: ~45cm (18"): buried March 7
Could call it a wind slab or persistent slab, trending towards a persistent slab. It appears to need a stiffer slab (1F and P) above well-developed facets (most prominent on E-NE-N-NW aspects). I saw this setup at the border between middle and upper elevations, but in terrain better described by "upper elevation" (exposed ridgelines). The problem was ugliest on a NE aspect, and the structure/stability changed quickly as you moved N or E from that specific aspect.

Terrain Use

We closed wind-loaded slopes steeper than about 35* where there were facets buried over 30cm deep (E-NE-N-NW aspects near and above 9000').

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