Observation: NWAC Forecaster

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Weather Summary

Scattered snow showers throughout the day. Light to moderate and variable winds. No blowing snow observed. The sun was warm enough to begin softening old snow on SE aspects below 6,000ft.

Saw 3 fairly recent D1.5 WL avalanches from E aspects below 6,000ft in lower Silverstar Creek.

Snowpack Observations

We covered some terrain and dug a number of test profiles to get a better idea of how the persistent slab problem with the late January PWL has changed.
Overall, the layer has gained strength, but tests still show it could produce avalanches. We had many sudden collapse results with compression tests, and some ECT's propagated. The Near Treeline elevation band appeared to have a more consistent slab and weak layer structure than alpine terrain that is more affected by wind. The recent sunny and warm weather have created thick melt/freeze crusts on SE-SW aspects, and consolidated the dry snow above the weak structure on shaded slopes into 1F to P hard slabs.
Of note, we were often finding surface crusts on shaded aspects from a drizzle/warm and humid event on the 9th/10th. This crust got buried by snow during the day, and will be known as the 'Valentines Day Crust' moving forward. It ranged from a thin zipper crust to supportable and smooth, but often presented as translucent ice from 0.5cm-1.5cm in thickness. Small grained facets were observed beneath the crust in many locations, and the crust would break away and separate easily from the facets beneath it.

Silverstar area
N at 6950: HS 168cm, CTM RP, CTM SC down 15cm on 1.5mm faceted melt forms between late January crusts. ECTN 15 on same layer. Grains were fairly sharp in this site as they were near the surface in an area that recent snow had been getting stripped off from winds.
In a site a few hundred feet to the north on an East aspect, the HS was 295cm, and the late January crust/facet complex was down 68cm. Facets were 1mm and rounding.

NE at 6,550ft HS 210cm:
CTM SC down 25cm above upper late January crust on 2mm rounded facets/melt forms.
CTH SC failed down 25cm and 28cm both above upper crust and beneath it.
ECTN down 25cm
PST 55/100 (End) down 25cm, but saw veered out of the layer.

Upper Cutthroat drainage:
ENE at 6,360, HS 329cm
CTM SC down 54cm on faceted melt forms between late January crusts. Upper crust was 0.5cm thick and P- hardness, facets were 1F-/4F hardness, lower crust 5cm thick and K hard.
ECTP H (21) down 54cm

Avalanche Problems

Problem	Location	Distribution	Sensitivity	Size	Comments
Persistent 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	Layer Depth/Date: 1-2ft Weak Layer(s): Jan 30, 2022 (FCsf)