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Missoula Avalanche

Professional Observation

Basic Information

Observation Details

Observation Date:
January 12, 2022
Submitted:
January 12, 2022
Observer:
WCMAC - David Fox
Zone or Region:
Southern Bitterroots
Location:
Boulder Point

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
Observed small wet loose slides on steeper NE aspects up to 6,500'.  The top 6" (15cm) of snow is saturated from rain and above freezing temperatures up to 6,500' on all aspects.  Also observed a wet snow surface 1/2" (1cm) from above freezing temperatures at 8300'.  

Snow Stability

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

Bottom Line

Above freezing temperatures combined with low to mid elevation rain has added water to the snow surfaces. Even in the upper elevations.
Observed denser wet snow (4F+) on top of low density snow (4F-) on shaded terrain in the upper elevation. BSH was identified below the low density snow and was reactive in stability tests.
Observed small point releases and small wet loose slides on steeper terrain, specifically NE/E aspects below 6500'.
Facets at the ground were rounded, frozen and unreactive in stability tests.
Very difficult trail breaking due to wet sticky snow.

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Temperature:
35F (2C)
Wind:
Light , SW

Temperatures were above freezing at all elevations ranging from 44F (7C) at 4500' to 35F (2C) at 8300'. Light rain in the morning gave way to party cloudy skies with brief periods of sunshine. Winds were clam below 8,000'. Above 8000' there were moderately strong SW winds at 10-15mph with gusts to 20mph. No wind transport of snow was observed.

Snowpack Observations

Height of snowpack at 8,150' was 265cm. Pit was located on a N aspect (25 degrees) with a 35 degree slope. Wind loaded area.

CT13 @ 25cm (SC) Denser moist snow/lower density interface.
CT18 (SC), ECTN13 @ 45cm . Failed on a rounding BSH layer from cold temps prior to all the recent snowfall. 1F density snow below the BSH layer provided a clean plane.

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