Observation: NWAC Observer
Basic Information
Observation Details
Observation Date:
January 16, 2023Submitted:
January 16, 2023Observer:
NWAC Observer - Brooke Maushund and Matt PrimomoZone or Region:
Stevens PassLocation:
Lichtenberg Area (W-S-E// 3300'-5700')Signs of Unstable Snow
Recent Avalanches?
YesCracking?
None ExperiencedCollapsing?
None ExperiencedMedia/Attachments
Advanced Information
Weather Summary
Cloud Cover:
Partly CloudyTemperature:
34°FWind:
Light , SWNew/Recent Snowfall:
HN 8-12cmSkies started out FEW with a lot of blue sky and sun warming up solar aspects. As we made our way up in elevation, sky cover increased to SCT with visibility still decent, and light snowfall (S-1) began at ~12:20, with light wind out of the SW. Precipitation lasted for ~1hr until we started our descent.
Snowpack Observations
As we travelled higher toward Lake Valhalla, we observed 8-12cm of fresh new snow from last nights storm on top of a stiff, but thin (0.5-1cm) ice crust (1/15). We were able to trigger small wet loose slides on test slopes (see video) as the new snow was not well bonded to the ice crust from our most recent rain event. Older (1-3 day old) wet loose slides abounded, ranging from D1-D2 in size, with some recent, shallow D1's appearing to slide today as the sun warmed things up. We observed some isolated wind affected snow at 4F- hardness, and up to 25cm deep. Most test slopes were largely unreactive. Above about 5,000ft, the new snow was noticeably drier, softer, and sparkling in the shade, suggesting that it was beginning to weaken.
Even with the new snow on top, ski crampons made travel much easier, especially NTL-ATL as the thickness of the ice crust increased. On an East aspect at 5,700ft, we got a Q3 BRK failure within the new snow, a short ways above the crust, which supported our findings while traveling uphill that the new snow wasn't well bonded to the crust. Conducting a deep tap and shovel tilt test, we were not able to pinpoint much instability deeper in the snowpack. The layer of snow just above the Christmas Crust is rounded to the point that we called them rounds, though could still barely make out a few flat faces (1F+).
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
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Wet Loose
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While we encountered some wind affected areas, the wind slab problem was isolated, small, and largely unreactive both in areas we travelled, as well as in terrain we could see at ridgeline elevation with good visibility. We did see multiple 1-2 day old wet loose slides up to D2 in size, as well as fresh wet slides in the D1 range that occurred during the day today.