Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

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

Cold temperatures and moderate wind speeds are keeping danger steady. You can trigger avalanches in wind-drifted snow and loose snow avalanches in steep terrain. Approach new terrain cautiously and evaluate the snowpack at upper elevations. You should also expect frigid temperatures and strenuous trail breaking.

Lawinenprobleme

  • Wind Slabs

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

    If you venture into the highest elevations, you may be able to trigger existing and freshly formed wind slabs in isolated areas. Old wind slabs from December 23rd may be unreactive, but steady, moderate winds are forecasted and will likely form new slabs at upper elevations. Observers at Mission Ridge reported two small, natural wind slabs, possibly triggered by a cornice fall on the night of the 26th. Be attentive and watch for actively blowing snow that may be building new and sensitive wind slabs. If you experience shooting cracks, hollow-sounding snow, or see recent avalanches, choose low-angle terrain.

    (12/27/2021)

    Blowing snow was observed in the Chiwakum Mountains in the East Central zone.

    Photo: Matt Primomo 

     

  • Loose Dry

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

    Continued cold temperatures are keeping the upper snowpack relatively cohesionless. This lack of cohesion can cause the new snow to run fast on steep slopes and entrain additional snow as it moves downhill. Look for signs of fan-shaped avalanches, or point releases, that typically start from a single location and spread out as the travel downslope. They can run naturally, or you can trigger them as you move through steep terrain. Use steep test slopes to see if dry snow accelerates and entrains snow as it moves. 

    As you gain elevation, these avalanches may become more likely and increase in size. Manage your travel carefully and know where your partner's location. Stay out from under other people in steep or consequential terrain and be wary of terrain traps such as creeks, trees, or cliffs that you could be carried into or over.

    Small Dry Loose avalanche in steep terrain near Dirtyface Mountain. Photo: Pat Riffie 

Avalanche Discussion

While we may be getting a short reprieve from the stormy weather, temperatures will remain chilly, with lows in the single digits and highs in the teens. So bring extra layers and be diligent with self-care to prevent cold injuries. 

The solstice crust is now buried 20 to 30 inches in western parts of the zone and 5-10 inches in eastern areas. While many reports have indicated the new snow is well bonded to this crust, there is a lot of uncertainty from the upper elevations. Stormy weather and rugged trail-breaking conditions have limited observations from the upper elevations. However, on December 27th, an NWAC forecaster observed a very large avalanche on Mastiff Mountain, on the eastern edge of the neighboring Steven’s Pass zone. While we are uncertain what interface this avalanche ran on, it warrants caution and careful observation as you venture into higher elevations and more complex terrain. Dig down to the Solstice Crust to investigate the reactivity of that interface. Use hand pits and test slopes to identify instabilities in the recent storm snow.  

A shallow and weak snowpack exists near Blewett Pass and Mission Ridge. In these easternmost areas of the zone, basal facets (weaker snow) may exist near the ground. This weak structure may be perpetuated by the extended frigid temperatures and become problematic in the future with additional snow.

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