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Professional Observation

Basic Information

Observation Details

Observation Date:
April 19, 2023
Submitted:
April 20, 2023
Observer:
PAC - Kevin Studley (off duty)
Zone or Region:
Boulder/Jughandle Area
Location:
East side of Jug

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
No signs of instability noted prior to the avalanche. I was looking for solar warming on south-facing slopes and evidence of wind slabs on east-facing aspects.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Moderate
Stability Trend: 
Improving

Media

Looking up at the crown of the avalanche. This slide failed on a layer of weak snow above the MF crust buried on Monday (04/17)
Looking down the track
You can see the evidence of an older avalanche on this adjacent slope
You can see the crown and flanks of recent avalanche activity to the right
View from ridgeline to the north
Wet loose slides were observed with afternoon heating
This photo highlights the day's weather

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Temperature:
Not observed
Wind:
Light , SW

The AM was very cold, clear, and sunny. Over a foot of new snow from previous 48 hours with SW winds. Wind direction shifted within previous 24 hours out of the NW.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Past 24 hours East side of Jughandle
NE 7900 		D2 SS I-New/Old Interface 12" AS-Skier
u-Unintentional 		This avalanche ran over 400 vertical feet, was approximately 75 feet wide, average crown depth was about 12", this was a soft, storm slab avalanche, it failed on a layer of weak snow just above the MF crust buried Monday (04/17), debris pile was an average of 3-4 feet deep, the slope angle near the crown was about 38 degrees
SS-ASu-R2-D2-I

I made multiple ski cuts below the ridgeline before committing to the slope. Soft, loose snow was observed with ski cuts. The avalanche was triggered right after committing to skiing the slope.

Terrain Use

Wednesday (04/19), I unintentionally triggered an avalanche while skiing solo. This was a very close call. Thankfully, I was not caught in this slide and I was able to ski away from this incident and reflect on what mistakes were made leading up to the avalanche.
There are six common heuristic traps leading up to avalanche accidents. An acronym (FACETS) is used to describe those human factors:
F- Familiarity (I skied this slope under similar conditions last year right around this time)
A- Acceptance
C- Commitment (I was very goal-oriented to ski steeper north and east-facing slopes)
E- Expert Halo (over-confident in my decision making skills to think I knew exactly what was going on with the snowpack)
T- Tracks, or social facilitation
S- Scarcity (bluebird, Spring, powder days are rare, this was an example of trying to ski soft powder before the April sun changed the snow)

Other factors:
- I did not see previous avalanche activity on the adjacent slope
- Traveling solo into steep, avalanche terrain. I was pushing too hard for solo travel that day
- I assessed snowpack stability previous to the avalanche but that was done on different aspects

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