Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 4, 2023
Submitted:
February 4, 2023
Observer:
NWAC Forecaster - Katie Warren
Zone or Region:
East Central
Location:
Little Wenatchee River Drainage (2000-5800ft; All aspects)

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
None Experienced

Media/Attachments

Wind features along the ridgeline. Cornice formations on both sides show the switching wind directions that have been common this winter.
I could push these small wind slabs where they formed over slick crusts along the ridge.
In the afternoon we could push small wet loose avalanches like these than ran on recently formed sun crusts.
Widespread rollerballs and pinwheels were present below 4800ft.
At valley bottom, rain in the afternoon had already formed drainage channels this the ones in this photo.
A snow profile at 5600ft and an E aspect showed an overall right-side-up snowpack with a weak layer of faceted snow over the MLK crust, indicated by the crystal card in this photo.
Faceted grains above the MLK crust.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
32°F
Wind:
Light
New/Recent Snowfall:
15-20cm HST, overnight

Light freezing rain at the trailhead transitioned to moist snow around 3500ft. The previous wind effect was evident, but the winds had died down, and we observed no blowing snow. Clouds seemed to thin around mid-day, but it was a short reprieve, and they thickened again by afternoon, bringing a return of some light precipitation.

Snowpack Observations

We found around 2" of new snow at the Little Wenatchee River Trailhead (2000ft) with a thin, fragile freezing rain crust on the surface. It was just enough to keep the sleds cool on the packed road.

At 4200ft on a South aspect, there was an HS of 90cm, with 20cm of storm snow over a thin melt-freeze crust (1/21). The MLK crust was supportable and buried 38cm deep in this location.

We navigated wind features along a ridgeline to 5800ft. Despite the obvious wind loading, we found wind slabs to be stubborn to unreactive in most locations. The exception was in locations where they formed over slick crusts where we observed cracking and could get small 10-20cm deep wind slabs to run with moderate effort.

We dug a test pit at 5600ft on an east aspect with an HS of 300cm. Overall we found this to be a strong right-side-up snowpack. A notable layer of small faceted crystals exists down about 60cm over the MLK crust, although test results produced no results (ECTX, CTN). The new/old snow interface sheared with easy force in a shovel shear test.

Exiting on southern aspects below 5000ft, we easily pushed small wet loose avalanches that ran on recently formed sun crusts.

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