Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Thu
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
Open full map
Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

If you’re going to trigger a significant avalanche Wednesday it will most likely be in steep wind-loaded terrain. Soft fluffy snow may hide some of the classic clues of wind-affected snow. Look for sharp cornices and drifts to indicate aspects you may want to avoid.

Lawinenprobleme

  • Wind Slabs

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

    Sustained winds during the storm likely built firmer slabs on the lee sides of ridges, along the base of cliffs, and in the tops of rock-walled chutes. However, as winds decreased and snow continued to fall, these slabs may now be buried under a few inches of snow. That means they could be harder to identify and ultimately navigate. 

    Look for larger clues like cornices and drifts to figure out local wind patterns and which slopes could be loaded. Assume wind slabs are hiding underneath the soft inviting powder in these areas until proven otherwise.

    Ease into the terrain by using smaller and less consequential slopes to see how the snow reacts. If you find cracks or feel firm hollow snow underneath you, dial it back and stay off of these suspected wind-loaded areas.

    Large sharp cornices like this can help you anticipate potentially wind loaded areas. (2/21/2023) Public Field Report: Phantom/thunder creek Photo:

Avalanche Discussion

Avalanche Fatality: Colchuck Pk, East Central Zone: Read the preliminary report here.

We’re just coming out from a stormy few days at the Pass. Reports from Tuesday indicate lots of generally right-side-up soft snow over the new crust. However, due to the strong winds and near constant precipitation, observations have been very limited. That means we aren’t quite as confident about the current conditions, especially higher in the terrain. We suspect a natural avalanche cycle occurred Monday evening during the height of the storm. So far, only the 4 larger natural slides observed by an NWAC forecaster on Monday have been reported to confirm this. 

Storm totals will vary greatly as you gain elevation. At Pass level, weather stations reported 6-8in of new snow, while higher in the terrain, several feet of snow has fallen since 2/19. 

On Tuesday backcountry travelers triggered a few small loose dry avalanches in very steep terrain, even below treeline. This pattern should continue Wednesday. Don’t be surprised if you see a few natural loose slides from steep rocky slopes.  If the clouds thin or the sun pops out for a moment, it could exasperate this issue. 

We expect most avalanche activity to remain in the new snow above the recent rain crust. However, we can’t rule out an isolated avalanche breaking into deeper layers like the 2/17 or 2/13 interfaces. This would be most likely with a larger trigger such as a cornice or smaller avalanche.

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