Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
November 23, 2022
Submitted:
November 23, 2022
Observer:
NWAC Forecaster - Matt Primomo
Zone or Region:
Stevens Pass
Location:
North side Lichtenberg (North half to 4,800ft, S slopes from afar.)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
Isolated

Media/Attachments

Coverage remains very thin on south facing slopes, where the sun has melted it down.
These natural slabs appeared to have ran during the tail end of the last storm (11/22). They ran on a layer of weak, sugary facets and a thin crust buried just beneath the recent storm snow. Similar activity was a common sight on the north slopes of Lichtenberg.
This natural slab appeared to have ran during the tail end of the last storm (11/22). It ran on a layer of weak, sugary facets and a thin crust buried just beneath the recent storm snow. Similar activity was a common sight on the north slopes of Lichtenberg.
These natural slabs appeared to have ran during the tail end of the last storm (11/22). They ran on a layer of weak, sugary facets and a thin crust buried just beneath the recent storm snow. Similar activity was a common sight on the north slopes of Lichtenberg.
A small slab on a boulder at 4,800ft with a person for perspective.
Can you spot the crown?
Profile from a north facing slope at 4,800ft on the north side of Lichtenberg.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Sunny
Wind:
Calm
New/Recent Snowfall:
8-12"

Nice, late fall day with temperatures warming up enough to melt snow surfaces on neutral aspects below 3,500ft by afternoon.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
8 Nov 22, 2022
() 		Lichtenberg Slabs
N 5000ft 		D1.5 SS-Soft Slab 1ft N-Natural
These natural slabs appeared to have ran during the tail end of the last storm (11/22). They ran on a layer of weak, sugary facets and a thin crust buried just beneath the recent storm snow. Similar activity was a common sight on the north slopes of Lichtenberg.
These natural slabs appeared to have ran during the tail end of the last storm (11/22). They ran on a layer of weak, sugary facets and a thin crust buried just beneath the recent storm snow. Similar activity was a common sight on the north slopes of Lichtenberg.
This natural slab appeared to have ran during the tail end of the last storm (11/22). It ran on a layer of weak, sugary facets and a thin crust buried just beneath the recent storm snow. Similar activity was a common sight on the north slopes of Lichtenberg.
A small slab on a boulder at 4,800ft with a person for perspective.
Report
Lichtenberg Slabs

See avalanche occurrences.

Snowpack Observations

We found a breakable rain crust on the surface from Smithbrook TH that extended up to ~4,200ft. Above that it tapered off to soft powder. Around 4,500ft we began receiving some direct feedback in the form of Whumphing. We found the culprit to be a thin layer of faceted grains and/or surface hoar on top of a friable crust, over a thicker layer of very weak, sugary facets. This layer can be attributed to the high pressure spell in November. We found this structure from 4,000ft up, and likely extends to ridgeline but we couldn't verify as we turned around due to obvious poor stability and recent avalanches. Whumphing and cracking became more frequent as we approached our high point at 4,800ft. We verified that the slides we saw were failing on this weakness with a profile, then skiied carefully through the thin cover and forest back to the road.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Storm Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 12"
Comments: May turn into a persistent slab problem with more snow.
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