Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

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

Kernpunkte

You'll likely encounter shallow wind slabs on a variety of aspects as east winds redistribute recent snow.  The combination of sun and slightly warmer temperatures raise the risk of cornice fall or a wet loose avalanche that could trigger a deeper avalanche in isolated areas.  Pay attention to overhead hazard and consider avoiding complex terrain at upper elevations. 

Lawinenprobleme

  • Wind Slabs

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

    Winds will shift to the E-SE on Wednesday night potentially forming new wind slabs on westerly aspects.  You'll want to use caution on any aspect you find recently drifted snow and can trigger a shallow wind slab, most likely below ridgelines, near convex rollovers, and in the tops of chutes.  These wind slabs may trigger easily but should remain fairly small and easy to avoid. 

    The more unlikely but consequential version of this problem will be isolated deeper wind slabs that may have formed a few days ago.  Deeper slabs are more likely to be found in higher elevation and cliffy terrain.  Following another round of snow and wind on Tuesday night/Wednesday,  2 natural slab avalanches released off of Chair Peak in this sort of terrain.  The best way to handle this problem is to stay off and out from under rocky complex slopes, especially where you see larger cornices. Snow shedding from above or other avalanches could release these slides naturally. 

    (3/15/2023)

    Shooting cracks in freshly wind-drifted snow.  It was easy to trigger shallow 3-4" wind slabs on test slopes.

    Photo: Dallas Glass

  • Loose Wet

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

    New snow from Wednesday will be primed to come down on steep sunny slopes. An easterly breeze and some uncertainty around the sunshine forecast may make this problem vary across the zone.  If you start to see pinwheeling, rollerballs or natural wet loose avalanches, it's time to change aspects or move to lower angle terrain.  While you don't want to go for a ride in a wet loose avalanche, also make sure to look up and take stock of the overhead hazard.  Don’t linger on or under steep sunny slopes.  With a crust just under the surface, some of these slides could travel quickly downhill.

    (3/14/2023)

    Lots of rollerballs and fresh wet loose avalanches occurred with sunshine in Snoqualmie Pass.

    Photo: Katie Warren

Avalanche Discussion

A convergence zone brought a quick 4-7" to Snoqualmie Pass  Tuesday night through Wednesday morning along with strong to moderate westerly ridgeline winds.  Professionals reported easily triggering shallow wind slabs and shooting cracks in wind-drifted snow near and above treeline.  Of more consequence, 2 natural avalanches released in the early afternoon off the north side of Chair Peak and ran down to Snow Lake.  One large wind slab avalanche was estimated at 2' and released at the base of cliffs.  A very large avalanche 4-5', released higher in the terrain and almost 300' across.  While rollerballs did start to gain steam during sunbreaks, mostly cloudy skies and cool temperatures likely held wet loose avalanches largely in check and may have staved off a new sun crust for another day.  

Below the new snow, you'll likely find a thin sun crust from Tuesday on steeper southerly slopes.  While there wasn't a widespread wet loose cycle Tuesday, sunshine caused new snow to shed from rocky faces. Some of this falling snow triggered wind slabs on the slopes below (see media gallery below for more examples). In each case, the avalanche failed at the base of a cliff soon after the sun began to warm the steep face above. On more shaded slopes, cold dry snow remains. The storm earlier this week dropped just over a foot of snow at mid and upper elevations around the Pass. 

With Spring slowly gaining a foothold in our region, glide avalanches and natural cornices failures are on our minds. If you see crevasse-like cracks or overhanging blocks of snow, keep moving. Don’t hang out under these looming unpredictable hazards.

Abgedeckte Regionen