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Professional Observation

       

Basic Information

Observation Details

Observation Date:
November 18, 2022
Submitted:
November 18, 2022
Observer:
Everett Phillips | ESAC Forecaster
Zone or Region:
McGee Creek
Location:
McGee Mountain - Sastrugi and Facets

Signs of Unstable Snow

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

Key Points

Today’s goal was to assess the Above treeline (ATL) snowpack on McGee Mountain. Here are the takeaways:

  • There is less snow here than on most mountains in the Mammoth Lakes area.
  • ATL and NTL wind has been scouring exposed slopes and terrain features on all aspects.
  • The wind packed snow is very hard (K hardness) and the deposits are thin. It feels more like a wind crust than a wind slab.

Overall, conditions in this area seem in line with the general advisory up on the ESAC website.

Media

Sastrugi facing multiple directions - the wind has come from all sides of the mountain

Advanced Information

Weather Summary

Cloud Cover:
Clear
Temperature:
Not Obs
Wind:
Light , NW

Below freezing temperatures.

Clear skies.

Light NW wind gusting to moderate.

Snowpack Observations

ATL and NTL on McGee Mountain:

HS: 10 – 50cm

The snow surface is Sastrugi in most areas. Where it is supportable this surface can provide efficient riding (it isn’t too rough).

Under the wind crust and in protected areas the snowpack is thin (~20cm) and weak (F hardness) – composed of small faceted grains.

I dug a hasty pit just below the summit (10800′ – ATL) on an E aspect. Slope angle was 30 degrees. HS~40cm. I found ~15 cm of knife hard wind crust on top of ~25cm of fist hard 1mm facets.

I did NOT find the rain crust that has been seen at the base of the snowpack in the Mammoth Lakes area.

10800' ATL, E aspect, 30 degrees

Terrain Use

The wind packed snow ATL is hard enough and slick enough that there is fall and slide hazard in certain areas.

Below treeline (BTL) sagebrush is the dominant snowpack factor.  I only traveled on 4WD roads below 9500′ to avoid it. South facing slopes BTL are mostly snow free in this area.

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