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Professional Observation

       

Basic Information

Observation Details

Observation Date:
March 25, 2023
Submitted:
March 26, 2023
Observer:
Everett Phillips | ESAC Forecaster
Zone or Region:
Mammoth Lakes
Location:
McGee - Mountain - Stubborn Wind Slab

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced

Key Points

I went out to McGee Mountain and skinned up the low angle east facing panel above round valley. The goal was to track  the 3/19 interface to 9000′ and see if the same problemtaic layering that has been reported from areas south of Bishop is present.

  • Did not find the PS problem on McGee today
  • Wind Slabs appear stubborn NTL
  • Where there was a signifcant slab from the last two storms the layer above the MFcr is wind packed rounds and did not show up in stability tests.
  • The 3/19 interface is down 1-2 feet as described in the forecast
  • Subtle changes in aspect lead to major variations in the character of the crust and the slab above it. In areas where signs of instability are present a subtle shift in terrain could change the likelihood of triggering an avalanche.

 

Media

Decomposing precip particles (weak), with a few near surface facets mixed in under thin wind board. Good close up of breakable crust.
Breakable crust on low angle NE from 7000' to 9000' on McGee.
Thin sun crust on top of the breakable wind crust on E and SE between 7000' and 9000' on McGee

Advanced Information

Weather Summary

Cloud Cover:
Mostly Sunny
Temperature:
30F @ 6800' at 11:30 AM
Wind:
Calm

Clear skies, calm winds, cool temperatures.

Snowpack Observations

9000′:

NE: Ski 5cm, Boot 20cm, HS 335cm, 3/19 interface down 50cm no MFcr. No persitent grains at interface. Interface unreactive in Compression Test. All results resistant planar

E:  Ski 0cm, Boot 10cm, HS > 300cm, 3/19 interface down 70cm Strong 10cm MFcr. No persitent grains at interface. Interface unreactive in Compression Test. All results resistant planar

ENE: Ski 15cm, Boot 25cm, HS >300cm, 3/19 interface down 55cm. Weak MFcr. No persitent grains at interface. Interface unreactive in Compression Test. All results resistant planar

 

8000′:

NE: 5- 10cm breakable wind board over 10cm decomposing and fragmented precip. particles. Secondary grain type is rounding near surface facets. 1mm max size.

SE: Wafer thin sun crust on the surface of the wind board.

N: Effcient travel in 10cm of settled snow with a bit of recrystallization.

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