Observation: NWAC Forecaster

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Weather Summary

Light s-1 snow all day. At least half of the new snow accumulated overnight. Snow line started well below 2,000ft in the AM, increasing to 3,400ft by 15:00. Calm below treeline with light breeze at 6,5000ft ridge, and no wind transport.

Avalanche Observations

#	Date	Location	Size	Type	Bed Sfc	Depth	Trigger	Photos	Details
1	Jan 12, 2023 ()	Cutthroat ck, Shangri La SE 6180ft	D1.5	SS-Soft Slab			AR-Snowboarder		Report

The only avalanches we observed were results from ski cuts/slope testing on a steep, unsupported feature. Small, intentionally triggered sluffs ran through a short, very steep cliff, stopping when the slope angle dropped below 35 degrees (L-ASc-D1-I, ~10cm deep).
In Cutthroat creek, other observers triggered a slab avalanche, 2 ft deep. See attached avy obs.

Snowpack Observations

Aside from minor sluffing in the surface snow, stability was good and we didn't find many immediate concerns for avalanche hazard. At the end of the day, slopes below 3,400ft were becoming moist, though no wet avalanche instabilities were observed.

As this was is a shallower part of the zone, we looked for weak layers and potential instabilities around the Christmas crust and in the upper snowpack due to a couple of recently reported avalanches that ran in somewhat older snow with unknown weak layers. We didn't find any buried surface hoar layers, and the upper snowpack was well-bonded to the Christmas crust. The crust, which is actually 3 separate ice crusts with thin weaker layers between, did product propagating test results within the matrix. It seems a bit unlikely that this scenario would result in a triggered avalanche given the upper crust was 0.5-1cm of solid ice. Unlike closer to Washington Pass, we found surprisingly well-developed facets near the ground. Snowpack tests didn't indicate that this weaker basal layer is contributing to the avalanche danger under current conditions.

Height of snow:
3,200ft- 130cm
4,900ft- 145cm
6,500ft- 175cm

Profile 4,900, NE
HS 146cm, HN24 12cm
Notable layers/interfaces:
121cm- decomposing stellars (DF), recent storm interface, possibly Jan 5th or 9th
89-86cm- 4F hardness, 0.3mm, rounds w some faceting rounds
86-79cm- 3 separate ice lenses (K-Ice hard) w weaker layers between (4 Finger hard), , grains were small (0.5mm) and mostly rounded, Xmas crust matrix.
20-0cm- 4 Finger hard, 2.0mm, rounding facets, Old November snow,
Test results:
@ 121cm- Tilt test- moderate, planar. Compression test- moderate, resistant (CTM(RP)). Extended column- no propagation (ECTN18)
@ 84cm- 0.5mm rounds w some faceting rounds. Below the upper crust of the Xmas crust matrix- Compression test- moderate, sudden (CTM(SP)). Extended column- no official results, tho propagation with additional loading (ECTP31).
@ 20cm- Deep Tap- moderate, break (DTM (BR))

Avalanche Problems

Problem	Location	Distribution	Sensitivity	Size	Comments
Dry Loose	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Comments: Not overly energetic, needed consistent 40deg slopes to entrain
Wet Loose	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Comments: Developing late in the day to sundown below 3,500ft

Didn't assess above treeline