Northwest Avalanche Center

Observation: NWAC Observer

All Observations

Basic Information

Observation Details

Observation Date:
March 12, 2022
Submitted:
March 12, 2022
Observer:
NWAC Observer - Drew Lovell
Zone or Region:
East North
Location:
Harts Pass Area (N-E-S 5800'-7300')

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

We avoided the rocky starting zone at top, choosing a well-supported entrance with less-variable snow depths and better quality.
High, thin overcast and filtered sunshine created "greenhouse" conditions, but snow surfaces on NW thru E aspects and low angle meadows remained preserved and stayed cold.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
32°F
Wind:
Moderate , SW
New/Recent Snowfall:
Just a trace of new snow in this zone, with some stellars lying undisturbed on the snow surface.

The moderate SW winds at ridge crest felt surprisingly cold, for a day dominated by palpable warmth with filtered sunshine through high overcast. We observed little to no recent transport, as most windward slopes had been previously scoured, pressed, or warmed by the sun.

We observed very minor Wet Loose activity around steep rocky terrain today, with minimal entrainment.

Snowpack Observations

Cold snow remained preserved through the day on NW thru E aspects. Any slopes tilted to the S warmed in the sun and subsequently refroze towards late afternoon, with the cold wind a contributor.
We felt a degree of suspicion towards previously scoured, rocky starting zones, largely of NW-N aspect, and thus avoided committing to slopes with entrances of this character.
We felt greater confidence in entering slopes with well-supported, less wind-affected entrances, and thus found great ski quality with less anxiety.
We allowed a large buffer for re-grouping zones and skied steep pitches one at a time.

In a profile at 6600' on a NE aspect we found:
HS: 270cm
The mid-Feb. interface was present (down 60cm) as a thin, weak melt-freeze crust, but was unreactive in tests.
The late-Jan. crust-facet assemblage was down 90cm and consisted of a 3cm thick layer of 4F- hard facets between weakening crusts. We did not have a lens today to assess rounding, but the grains continue to exhibit weakness (easily "pouring out" from between crusts). Of note is the strength of the overlying slab, which trends from F-hard in the top 15cm down to 1F hard in the 50+cm over the late Jan. interface. Tests yielded CTH(SC, 22) x 1 and ECTX.

We observed patchy 1-2mm surface hoar, lying flat over the F hard upper snowpack.

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