Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
December 14, 2021
Submitted:
December 14, 2021
Observer:
NWAC Forecaster - Irene Henninger
Zone or Region:
West Central
Location:
Mountain Loop- North (N, E, S, 1800-4600ft)

Signs of Unstable Snow

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

Media/Attachments

Snow cover in treed areas at about 2200ft.
D1 avalanche which failed on smooth, steep rock slab at 3000ft (Dec 11-12?). Coated by ~5cm of snow and more recent moist rollerballs (likely from Dec 13).

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Temperature:
21°F
Wind:
Calm
New/Recent Snowfall:
130cm over Early Dec crust @4600ft.

Primarily obscured skies with infrequent small patches of blue skies popping through occasionally. Very light (S-1) snowfall intermittently throughout the day, amounting to ~ 4cm.

Only signs of avalanches were D1-1.5 that failed on steep (50+ degree) smooth rock slabs mid-storm (probably Dec 12). Elevations were at about 3000ft.

Snowpack Observations

Snow cover at 1800ft was moist and about 25cm in depth. Travel on skis became easier at about 2500ft, while coverage was excellent from 3000-4600ft (dry, 80cm-200cm snow depths, respectively). I began finding the Early December Crust at approx 2800ft.

Frequent hand shears revealed a generally well bonded right side up snowpack above the Early December Crust. I gained elevation and the new snow amounts no longer made it possible to do hand shears. I dug 2 pits with similar results on opposing aspects at 4600ft. Both were generally right side up aside from the one notable layer being a 4cm graupel layer approx 40cm down. Shovel shears failed easily on that layer, but compression tests were inconsistent and didn't fail all the way through on the graupel layer. Ski pen was ~20cm, boot pen was ~40cm.

No new signs of wind loading were present where I traveled.

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