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Missoula Avalanche

Professional Observation

Basic Information

Observation Details

Observation Date:
March 28, 2022
Submitted:
March 29, 2022
Observer:
WCMAC - Trask Baughman
Zone or Region:
Seeley Swan
Location:
Swans, Sunday Mountain

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Snow Stability

Stability Rating: 
Very Poor
Confidence in Rating: 
High
Stability Trend: 
Steady

Bottom Line

Today we rode sleds into the west side of the Swans near Sunday Mountain and Clearwater lake. Nearly every avalanche path in the Swans had evidence of past wet slides from the last few days.
It did freeze in the Seeley area last night. The snowpack had very little cohesion by midday. For example, the skis on my sled were starting to punch through the surface on the groomed trail.
While investigating a large D2+ slide that had occurred naturally early in the day around lunchtime, we witnessed two wet slabs simultaneously start from just north of Sunday Mountain. Both slides funneled and converged together, and we could hear trees breaking as they moved down the path. This slide could have easily destroyed a single-family (D3). The estimated slide path length was one mile long, 2400ft of vertical fall, and 600ft wide at the debris pile. We believe the trigger was a point realise from a cliff band near the summit that then stepped down to rock and ground.

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Weather Summary

Cloud Cover:
Mostly Sunny
Temperature:
above frezzing, 70f at the trailhead
Wind:
Calm
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