Observation: NWAC Observer

All Observations

Basic Information

Observation Date:

March 15, 2023

Submitted:

March 15, 2023

Observer:

NWAC Observer - Willie Webster

Zone or Region:

East North

Location:

Baldy Pass (All aspects 2400' to 7800')

Recent Avalanches?

None Observed

Cracking?

Isolated

Collapsing?

None Experienced

Descent sized cornices hang over steep terrain

Very small wind slab from recently drifted snow

Removing the column above a weak layer after a sudden planar result in a compression test (CTE 5 SP @ 75cm). This layer did not respond to an extended column test.

While winds were moving West to East today, the rhimed trees and wind scoops indicate a recent histroy of SE winds

Looking towards the North side Mount McCay which burned in the 2006 Tripod Fire

Textured snow surface shows signs of recent wind transport

Storey Peak, Gardner Mountain, and North Gardner

https://youtu.be/EELr-Kq91gA

Advanced Information

Cloud Cover:

Mostly Sunny

Temperature:

23°F

Wind:

Moderate , W

New/Recent Snowfall:

10"

Great visibility today with few clouds. While mostly sunny, temps stayed near 23 degrees throughout the day. There was a moderate west wind through the morning. Blowing snow could be seen trailing off nearby peaks. By the afternoon winds backed off to light or calm.

It's great to get out and take a look at the mountains and snow pack in this Easternmost part of our forecast zone. The snow pack was thin in the low country as we approached the mountains, but above 6000' the height of snow stayed between 4' and 7' deep. There is a subtle crust 4-6" down in places. The wind effect is considerable in this range and the height of snow can vary considerably. Today the winds out of the west were building small wind slabs on East aspects. By contrast, most of the storms of late February and March came from the SE and deposited snow on North and West aspects with 2-3' of somewhat recent soft snow in places. Descent sized cornices hang over steep terrain features. All this new snow since late February sits atop an older faceted snow pack. In spite of this structure, there weren't in-your-face red flags from the snow pack, maybe a couple yellow flags. I did not see cracking in this snow, no wumphing collapses, no triggers on small test slopes, and no results in an extended column test (ECTX). I did get a sudden planar result in a 30x30cm compression test (CTE SP @ 75cm). The weak layer here appears to be the faceted snow just below a very subtle mid-February crust. Under magnification this faceted snow appears to now be rounding, and we can assume settling under a couple feet of snow. It's worth pointing out that we have very limited observations from this corner of the East North zone.

Problem	Location	Distribution	Sensitivity	Size	Comments
Wind Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5
Cornice	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5

While I'm not listing the deeper weak layer mentioned above, perhaps a larger trigger in an isolated spot could initiate a large avalanche.

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