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Missoula Avalanche

Professional Observation

Basic Information

Observation Details

Observation Date:
December 7, 2022
Submitted:
December 7, 2022
Observer:
WCMAC - Arden Feldman
Zone or Region:
Other
Location:
Lolo Pass, Crystal Amphitheater

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
Isolated

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Low
Stability Trend: 
Steady

Bottom Line

Today we toured in the lower Crystal Amphitheater zone. Skies were overcast, trending towards broken as we were leaving around noon. Temperatures were relatively warm. We measured an air temperature of 28 degrees Fahrenheit at 5400 ft at 11 am. Winds were light to moderate out of the southwest.

Media

Cracking on wind loaded test slope.
Some wind affected snow surfaces in Crystal Amphitheater. Still lots of stumps and bushes to avoid.
Still lots of stumps and bushes to avoid.

Advanced Information

Snowpack Observations

We travelled on southerly and easterly slopes between 4800 ft and 6200 ft. On these slopes we found isolated signs of instability. Whumpfing and collapsing was more prevalent on flatter slopes and more shaded easterly slopes above 5500 ft. We dug a snowpit on a SE aspect at 5400 ft and found 2.5 ft of snow. The top 18 inches consisted of decomposing snow grains from recent snowfall. Below that, there were 12 inches of variable melt freeze crusts and facets. Stability tests did not produce any significant results. See pit profile for more details. On more exposed sub ridges with fewer trees, we found wind effected snow surfaces including sastrugi, wind skins, and wind board. Signs of wind slab instability were stubborn but a small, east facing, wind loaded test slope produced cracking 6" deep when jumped on.

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