Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
March 18, 2022
Submitted:
March 18, 2022
Observer:
NWAC Forecaster - Matt Primomo
Zone or Region:
Stevens Pass
Location:
Whitepine Road (NW-NE 2,300 - 5,800ft)

Signs of Unstable Snow

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

Media/Attachments

Cracking on facets just above the crust.
Profile NW aspect at 5,500ft with a thin layer of weaker, faceted grains outlined on both sides of the probe, just above a stout crust.
Profile N at 5,800ft, with the top of the stout early March crust outlined on both sides of the probe, and weaker faceted grains above. Old rain runnells can be identified on the left wall, with a wavy surface.
Sifted in wind slab off a ridgeline. NE at 6300ft.
Profile from N aspect at 5,800ft.
Weak layer of 3/8 facets identified above the stout crust from early March.
Wet loose slides off Mt Howard.
Bottom of 3/8 faceted layer flipped upside down.
Rock Mountain looking like spring down low, and winter up high.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Wind:
Calm

Cool morning, but warmed up with a little bit of greenhousing noticed towards the mid afternoon. Clouds lowered at one point in the afternoon, and picked up a few flakes of snow, but then dissipated and the peaks were out again across the valley.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Mar 15, 2022
() 		The Swath
NE 6300ft 		D2 SS-Soft Slab 1.5ft N-Natural
Sifted in wind slab off a ridgeline. NE at 6300ft.
Report
The Swath

Snowpack Observations

Lower elevations still have plenty of snow on these shaded aspects, and evidence of the Feb 28 avalanche cycle is aplenty. Many gullies and avalanche paths in this vicinity ran around that timeframe. The snowpack is now mostly supportable and well-transitioned to melt forms below about 4,400ft.

Above 4,400ft I found newer snow, though moist up to about 5,000ft. As low as 4,800ft I found evidence of the 3/8 faceted layer, but the layer was spotty to find and moist. Skinning from 4,400ft to 5,500ft was sometimes tricky with old debris, and the slippery crust not too far beneath the surface (15-25cm avg).

At 5,500ft on a NNW aspect I found a more consistent faceted layer and dry grains above the early March crust. Here I dug a profile in an obvious wind pillow. HS 214cm.
The 3/8 facets were down 30cm, only 1cm thick, 1mm and rounding but dry. Test results were:
Tilt Test moderate, planar
ECTN H down 30cm
PST 35/100 (End) down 30cm
PST 50/100 (End) down 30cm

Another profile on a N aspect at 5,800ft showed HS of 243cm
3/8 facets were down 27cm, 2cm thick, 1-1.5mm, rounding/dry and weak (F+). Test results were:
CTM SP x2
ECTN H
PST 25/100 (End)
PST 35/100 (End)

I was able to get localized cracking on skin track tests from time to time. I didn't get any whumphing, but had I continued up into areas where the snow was deeper/thicker wind drifts I would've expected it. The snow surfaces became slightly moist even on N aspects at 5,800ft by 3pm, with some rollerballs releasing on my way back down at 5,000ft or so.

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