Lawinenlagebericht

West Slopes North

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Steep rollovers or other types of unsupported terrain are where you are most likely to trigger an avalanche. Use planar and/or lower angle terrain to navigate around these features and reduce risk. Obsevations of active windloading or signs of instability like whumphing or shooting cracks are a signal to switch to a more conservative plan for the day.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Existing wind slabs will be the greatest hazard on Thursday. If northeast winds are stronger than forecast, expect to see abundant loose snow transported into new slabs. Take a step back in your terrain choices if you observe active wind loading.

    The current crop of slabs could be difficult to identify with a powdery surface layer hiding signs of recent wind loading. Use cornice like features to identify the loading pattern during the latest storm. Monitor new snow depth in sheltered areas and use this as a reference in more wind exposed terrain. Shallower new snow or a firmer surface at or just below the snow surface is a great indicator of lurking wind slab.

    Simple hand pits let you investigate the relative difference between wind stiffened layers and weaker snow below. Test slopes - especially on wind drifted features - can give you an idea about the reactivity of wind slabs in the immediate vicinity (photo).

    There is still quite a bit of new snow out there. Stay alert in lower elevation terrain and keep assessing new snow layers. Don't forget about the consequencse of exposed terrain obstacles, open creeks or gullies below.

    Shooting cracks like these are reliable  indicators that a reactive wind slab exists nearby.

Avalanche Discussion

West North picked up 12” in the Sisters Range and 19” at Heather Meadows. The Cascades south of Highway 2 picked up notably more snow. While storm totals in West North generally did not meet expectations, no one enjoying exceptionally good riding conditions Wednesday seemed to take issue.

Even with the recent snowfall there was little in the way of natural avalanche activity noted other than small loose dry's and a single D1 soft slab triggered by a loose snow avalanche from above (Bagley Basin, photo). Avalanche mitigation work produced numerous but generally small avalanches in very steep, unsupported terrain. No notable human triggered avalanches were reported. 

The lack of avalanche activity points towards a strong snowpack. On the other hand, one team in the Baker Backcountry experienced a single large whumph near treeline on Wednesday. A nearby snowpit indicated rounding facets between crust layers +100cm down (photo). No similar instability or snowpack observations were noted in the past week. Observations like this remind us to not take the snowpack for granted, especially during colder weather when weak snow is more likely to develop and linger.

One person was fully buried - but quickly recovered - in a short, steep gully feature in backcountry terrain adjacent Mt. Baker Ski Area. Details are sparse, but it appears it was a small loose dry triggered either by the victim or someone above. Though this avalanche was very, very small, it still highlights both the need to be aware of terrain traps below and good communication with those around.

If you are out and about in the mountains, let us know what you find by submitting an observation. 

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