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Professional Observation

       

Basic Information

Observation Details

Observation Date:
January 8, 2023
Submitted:
January 8, 2023
Observer:
Everett Phillips | ESAC Forecaster
Zone or Region:
Mammoth Lakes
Location:
Mammoth Lakes area - Deep Snowpack

Signs of Unstable Snow

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

Key Points

I went out in the Mammoth Lakes area to have a last look at the upper snowpack layers from the last three storms

  • Total height of snowpack ~ 3m (10 ft.)
  • HN24: ~ 15 to  25 cm
  • Storm slabs were unreactive on convex rolls BTL
  • The upper snowpack (within 170 cm of the surface) consists of wind packed precipitation particles from recent storms. No persistent grains were found.
  • Dangerous tree well (snow immersion suffocation) conditions are developing. If you are riding in the forest; keep your partner in sight.

It was eerily quiet and foggy out there. You could feel the storm coming.

 

Media

Tree well. Heavy snowfall over multiple days increases the risk of tree well accidents.
Shovel tilt test showing interfaces between layers of wind slab in the upper snowpack. None of these layers are especially concerning. No persistent grains between the layers, and no results with ski tests on test slopes.
Freezing fog deposited ice and rime on trees.
Calm and fog before the storm. NW Aspect 10,000' Mammoth Lakes.
20230108. NW, 10,000', HS: 450cm, slope angle 25 degrees.

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Temperature:
23 F
Wind:
Light , SW

Storm intensity decreased this afternoon. At 10,000′ on a NW aspect graupel was falling at less than 1 inch per hour, and winds were light with moderate gusts from the southwest.

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