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Professional Observation

Basic Information

Observation Details

Observation Date:
March 18, 2022
Submitted:
March 18, 2022
Observer:
WCMAC - Jeff Carty
Zone or Region:
Central Bitterroots
Location:
Brushy Fork

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced

Snow Stability

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

Bottom Line

It was possible to trigger an avalanche on the faceted layer that sits on top of the March 1st rain crust today. Convexities that roll to over 35º are the most likely place to trigger a slide.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
32ºF (0ºC)
Wind:
Light , W

Warm temperatures today, hovering around 32º at 7600' this afternoon, above freezing below 6500'. Scattered snow showers today with negligible accumulations. Winds were light with moderate gusts, minimal snow transport observed.

Snowpack Observations

Similar snowpack we've been observing all week. Facets sit on the March 1st crust, which is buried up to 45cm deep in this location, to about 7200' in elevation.
The facets are propagating consistently in the propagation saw test, but not consistently in the ECT. The new snow lacks the strength to transmit the propagation across the block in the ECT, it breaks during taps, limiting the length of propagation. The PST shows that propagation is likely.

Test results
ECTN11 down 45
ECTP22 down 45
PSTend 40/100
PSTend 36/100

We were able to kick off small slabs that slid on the crust/facet layer on very steep convexities and unsupported slopes. They did not propagate much past the end of our skies and were confined to the steepest sections of rollovers.
We experienced no whumphing or cracking today.

Terrain Use

We skied terrain over 35º that was planar and supportive. We were careful to avoid convexities.

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