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Missoula Avalanche

Professional Observation

Basic Information

Observation Details

Observation Date:
March 4, 2022
Submitted:
March 4, 2022
Observer:
WCMAC - Jeff Carty
Zone or Region:
Southern Bitterroots
Location:
Lost Trail Backcountry

Signs of Unstable Snow

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

Snow Stability

Stability Rating: 
Good
Confidence in Rating: 
High
Stability Trend: 
Steady

Bottom Line

Below the rain line, roughly 8000', the snowpack is refreezing and is capped by a thick crust. There is a low likelihood of triggering an avalanche.
At and above the rain line, on north aspects buried facets are capable of producing an avalanche.

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Temperature:
23ºf (-5ºC)-17.5º F(-8ºC)
Wind:
Light , N

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Within the past week Eeny meeny miny
N 8000'
D2.5 SS I-New/Old Interface 12" N-Natural Storm slab avalanches released sometime mid storm this week. They have been partially reburied and are covered in wet loose debris from the past two days.
2 Past 48 hours Saddle Mountain
S 8400-7000'
D3 WS I-New/Old Interface N-Natural We could only see the bottom of the path due to clouds. There is a large pile of wet debris that scoured the snowpack in the path. No image due to poor visibility. None

Snowpack Observations

Below 8000' there is a mostly supportable crust, it can surprise you with thin spots that make skiing interesting though.
Above 8000', lower on north slopes, the crust is not supportive.
Around 8000' on north aspects boot pen is as much as 36" due to a faceted snowpack, other aspects are more supportive below the breakable crust.
We found propagation on a layer of facets 24" (62cm) down.
ECTP 29
PST end 35/100

At 7000' there is a thick crust, the snowpack is saturated below this and still moist.
Ice columns penetrate the snowpack where water percolated in during the rain.
Tests produced no results in this location

Terrain Use

We stayed off slopes over 35º on north aspects above 8000' due to poor structure and propagation in tests.
We stayed as mellow as possible on the decent on other aspects due to very poor skiing conditions.

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