Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
January 31, 2023
Submitted:
January 31, 2023
Observer:
NWAC Forecaster - Josh Hirshberg, Katie Warren
Zone or Region:
East Central
Location:
Upper Naneum Creek (4080-5900ft, all asp)

Signs of Unstable Snow

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

Media/Attachments

Wind textured snow surface. 5,300ft, Diamond Head Pk
Snow profile. Height of snow 94cm. The card shows the 1/4 surface hoar, which produced propagating test results (ECTP28, CTH(RP)). Mt Lillian South, 5840ft, W.
The Jan 4th buried surface hoar is large (8.0-10.0mm) and was found 40cm below the surface in upper Naneum Creek.
Large (2.0mm) facets found near the ground are widespread around the Blewett Pass area.
The southeast face and east ridge of Mt Stuart, viewed from near Diamond Head, Blewett Pass.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Wind:
Moderate , NW

Overcast skies in the AM becoming broken by noon. Cold start to the morning, warming to near freezing at midday. Wind exposed terrain saw moderate NW gusts, tho only light blowing snow due to firm surfaces.

No new avalanches. The most recent activity in the area were rollerballs and small wet loose slides in steep, rocky terrain from 1/25-26.

Snowpack Observations

The upper snowpack was generally firm with at least a thin layer of weak, facetted surface snow on the very surface. Up to 10cm of dry snow over the most recent crust (1/26). We noted an overall lack of surface hoar and saw it in only isolated areas.
Wind-exposed terrain was firm and textured, either scoured or old unreactive wind drifts.

Profile- Mt Lillian, 5,840ft, W
HS 94cm, Boot pen 20cm
Notable layers:
84-82cm: F hard, facets (2.0mm)
82-77cm: P hard, MLK crust
53-52cm: 4 Finger hard, surface hoar (8.0-10.0mm), Jan 4th, ECTP28, CTH(RP) @53cm
15-0cm: F-4 Finger hard, facets (2.0mm), Dry @ 15cm but moist near ground
Notable tests: Propagating Extended Column test on the Jan 4th buried surface hoar.
Implications: While it's currently unlikely to trigger an avalanche on the Jan 4th SH due to stout overlying crusts, it could be a problem weak layer with a future load or wetting from melt-water.