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Missoula Avalanche

Professional Observation

Basic Information

Observation Details

Observation Date:
February 9, 2022 - February 9, 2022
Submitted:
February 9, 2022
Observer:
WCMAC - Ryan Sorenson
Zone or Region:
Seeley Swan
Location:
Lodge Pole Creek

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
None Experienced

Snow Stability

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

Bottom Line

Our main concern was wet avalanche problems. Temperatures are elevated, and snow is melting. We chose to in simple terrain because we were new to the area. Observing a recent large loose wet avalanche (L-N-R2-D2) on the snowmobile road to Lodge Pole Creek trailhead confirmed this plan.
• Snow surfaces were sticky and moist below 6,000 feet.
• Strong previous winds have built large cornices above northeast aspects.
• The temperatures at a pit we dug on a north aspect near 6,200 feet was 37°F (3°C) at 2:00 p.m.

Media

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Temperature:
37°F (3°C)
Wind:
Light , SW

It was raining until we reached the trail head (10 a.m.). Broken skies were holding in lots of heat after that.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Past 48 hours 3.3 miles from Monture Guard Station
S 4300
D2 WL G-Ground N-Natural
u-Unintentional
Large loose wet avalanche that slid on steep 40 degree terrain under steep cliffs near 4300 feet. It ran approximately 300 feet starting around 4,600 feet elevation. Burnt trees up 10 inches in diameter were pushed over. An inch of recent snow covered the debris.

Snowpack Observations

We dug a pit on a north aspect at 6,200 feet. 20cm of moist, clumped, rounded snow sits over dryer layers. Rounding facets were found between mid-January crusts. No notable test results were observed.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wet Loose
Isolated
Specific
Widespread
Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
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