Close

Professional Observation

       

Basic Information

Observation Details

Observation Date:
December 25, 2021
Submitted:
December 25, 2021
Observer:
Steve Mace | ESAC Forecaster
Zone or Region:
June Lake
Location:
Chicken Wing. Several signs of instability

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
None Experienced

 

 

Snow Stability

Stability Rating: 
Poor
Confidence in Rating: 
High
Stability Trend: 
Worsening

Key Points

Our key takeaways today,

  1. Stability was deteriorating this afternoon as our next storm event enters the area.
  2. Triggering an avalanche would be easy today in the right location.
  3. Terrain features over 30° in steepness were showing signs of instability, particularly in leeward catchment zones.
  4. Significant amounts of snow are being transported even below treeline.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Temperature:
22°F
Wind:
Strong , SW

Partly cloudy skies prevailed this morning with intermittent snow showers and strong winds out of the SW.  looking North of our location the storm appeared to have arrived a bit earlier with June lake, and the mountains to the north socked in at around 9 am. non-the-less the storm moved into our area at around 11 am and by noon we were experiencing pretty heavy snowfall. Temperatures remained cold throughout the day with the added wind chill to make us glad to have our puffy layers.

Avalanche Observations

We triggered several small avalanches today. All were triggered intentionally. The most significant one was right of the ridge at 9700′. This sensitive windslab broke within the new snow and had a depth of around 40 cm.  fresh cornices along the leeward side of the ridge were quite sensitive as well and triggered small pockets of WS below when they broke loose.

We also observed deep shooting cracks below treeline, in more exposed areas, and on steep test slopes the biggest of which was about 100′ long. Several of these terrain features also produced small avalanches 1-2 ft in-depth and running within the new snow.  I believe we saw signs of instability supporting the potential for both Sensitive wind slabs as well as sizable storm instabilities.

 

 

Close