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Professional Observation

       

Basic Information

Observation Details

Observation Date:
December 27, 2022
Submitted:
December 27, 2022
Observer:
Everett Phillips | ESAC Forecaster
Zone or Region:
Convict Creek
Location:
McGee Creek to Tobacco Flat

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
Isolated

Collapsing observed below 8000′ in the sage zone, where shallow HS and full depth saturation combined to weaken the snowpack. No signs of instability above 8000′.

Key Points

Went up and over McGee to get a sense for changes in precipitation type and rate with elevation.

  • Snow levels and temperatures fell throughout the day.
  • Snowfall intensity increased with elevation. Near treeline (10000′ to 10700′) snow was falling at 5-10cm per hour.
  • Winds were light mid-slope, but moderate to strong on ridges.
  • I found evidence of rain at the start of the storm within snowpack up to 10000′ (see photo in gallery)
  • There was 30-60cm of new snow above 10,000′

Good to be out storm skiing in the maritime!

 

Media

Profile of the upper snowpack during the 12/27 storm.
Collapses and cracks below 8000'.

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Temperature:
26 F @ 10,000'
Wind:
Strong , SW

Terrain Use

Full avoidance mode today. I got into some steeper terrain below 9000′ where the ground anchors were visible above the snow surface (HS below threshold for slab avalanche activity). When it rains on a weak early winter snowpack, I tend to be careful about staying out of runouts of avalanche paths above me.

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