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Eastern Sierra Avalanche Center

Public Observation

Observation Details

Observation Date:
April 9, 2023
Submitted:
April 9, 2023
Zone or Region:
Bishop Creek
Activity:
Skiing/Snowboarding
Location:
North Lake

Observations

Spent the last 3 days (4/7-4/9) camped up in the North Lake zone. In general, found stable refrozen snow/corn on S aspects up to ~ 12k - above that S aspects not totally transformed to consolidated spring snowpack but getting there. On all other aspects, snowpack is transitional expect for cold snow on Northerlies above ~ 11.5k (likely higher after today?). Multiple hasty pits dug on all aspects from 9-11k, and widespread PWL found as a thin facet layer on top of a thick ice crust about 40cm down on all aspects except S (ice layer present on S about same depth but well bonded to it). Was not able to get propagation in any ECTs, but did get extremely clean shears every time when prying off with shovel, and did get a few CTH results on column tests, all on the same layer. While results didn't suggest reactivity, and no cracking/whumpfing was observed, structure was very concerning and kept us off anything steep non southerly. It seems like a structure that is healing with heat and time but also still present enough to cause isolated issues or maybe could produce wet slabs on top of that ice layer with some more warming?

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Wet Loose
Size:
Size 1: Relatively harmless to people
Elevation:
11-12k
Aspect:
Comments:
Many wet loose slides on 4/8 and 4/9 on steep Polar aspects, starting around 10am both days. D1

Also saw evidence of a deeper natural release either thick windslab or persistent on N aspect around 11.5k. Looked at least a few days old, maybe older. (D2?)

Media

Signs of Unstable Snow

None reported

Media

representative profile of general PWL issue seen.  2nd crust is the issue
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