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Deep slab, or maybe glide slab on Chicken Bones
Location Name:
Chicken Bones
Observation date:
Tuesday, March 23, 2021 - 09:30
Is this an Avalanche Observation:
Yes
Observation made by:
Public
Location
Tabs
Quick Observation
Spotted an approximately fifty-foot wide crown on Chicken Bones. Photograpy difficult in the morning light. Did not see ski tracks.
Much deeper than a current storm slab. Estimate around two feet.
Possible that it was a glide avalanche, with the ground covered up by recent snow.
Debris from this release triggered a much wider storm slab below. Estimate 6-8 inch crown. Could not see entire crown, or any of the debris.
The forecasted sunshine made an appearance in the morning, but at 10:30 a.m.,the area was blanketed in a cloud. This coincided with the winds shifting from light N to light S.
Temps remained below freezing in the shade all day above approximately 5600'.
During sunny periods before noon the snow on steep SE- facing slopes became moist and skier-triggering of rollerballs occured on 35 degree slopes.
There were more clouds than sun, at least until 4pm. The snow that was beginning to get moist froze into a zipper crust in the afternoon..The 6-8 inches of new snow on the recent MF crust stayed dry under this crust on 30-38 degree SE-facing slopes between 6400' and 5200' and on those with more Easterly aspect.
Though the new snow was upside-down, with the top inch being a bit denser, I saw no sluffing, no cracking. Hand tests and skiing above the skin track indicated a decent bond to the crust, with not much of a slab, being barely anke-deep.
There was a graupel layer in the top third of the storm snow.
Due to the cooler than forecast conditions the decision was made to lap SE facing slopes all day rather than head to northerlies.
Skied pitches up to 38 degrees in the afternoon without rollerballs, sluffing, or cracking.
West-facing slopes steeper than 30 degrees had an impressive rollerball cycle when the sun finally came out after 4pm.
Never had a sticky part of the day. S-facing lower elevation slopes had a speedy but soft crust that skied like corn by 5pm.
Previously reported glide activity has progressed on Big Slide, with an impressive crack.
Some of those ski tracks cross below this glide crack.
Snowpack, Avalanche, Weather Images:
Travel Details
Region:
Whitefish Range - Southern (south of Coal Creek)
Activity:
Skiing
