Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist last year abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You could trigger avalanches in isolated pockets of wind-drifted snow in steep, confined features below sharp ridgelines. Consider steering around steep slopes with stiff snow drifts. It's springtime, so if the sun is warming sunny slopes, wet avalanches are possible.  

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Recently formed wind slabs are likely gaining strength and may be hidden by a few inches of fresh snow that fell with light winds. But in steep alpine terrain, particularly confined features, you could get surprised by a small slide. Make frequent assessments as you travel and enter new terrain features slowly and cautiously. If you observe cracking, recent avalanches, or the snow feels stiff and hollow, you're more likely to trigger a wind slab. We expect wind slabs to be small and shallow, but they could still ruin your spring plans if you get caught in consequential terrain. 

    Use quick hand pits or small test slopes to see how the snow reacts before committing to steep, alpine terrain. If snow slides easily, dial back your terrain choices. 

    (1/5/2023)

    An example of a shallow wind slab you could trigger in steep lee terrain below ridgelines at higher elevations.

    Photo: NWAC Public obs

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    2–3

    If you're venturing into upper elevations east of the Cascade crest, take time to dig and look for potential weak layers in the top 3-4 feet of the snowpack. Stiff snow over softer snow layers deep in the pack is a key indicator of the potential for these consequential avalanches. When in doubt, choose more conservative, simpler terrain. 

    There is uncertainty surrounding older, weaker layers of snow. If you are in upper elevations or far east of the Cascade Crest, there might not be thick melt-freeze crusts over older weak layers. In these areas, east of Mazama and Hart's Pass, there may still be a chance of triggering persistent slab avalanches, where a shallower, weaker snowpack structure exists. 

    (3/17/2025)

    A widely propagating avalanche near Tiffany Mtn.

    Photo: Willie Webster

Avalanche Discussion

Wednesday is likely to have more clouds than sun, but spring weather is fickle and hard to forecast. The eastern and southern portions of the zone have a slightly higher chance of prolonged sunbreaks. It doesn't take long for the sun to warm fresh snow and quickly turn into a wet loose avalanche cycle. Wet avalanches could run farther than you anticipate on underlying crusts. While these avalanches are more predictable than slabs, they have a lot of mass and can be difficult to get out of if you are caught.  Move to lower angle or shady terrain if you start to see pinwheels and rollerballs, the first sign of wet avalanche problems. The springtime shedding of rock slabs and cornices can also increase with solar warming, so don't linger beneath these overhead hazards. 

On Monday, WSDOT forecasters in the Highway 20 corridor reported easily triggered dry loose avalanches on steep terrain at mid and upper elevations. The crust from the previous warm temperatures was moist at lower elevations, getting more supportable at higher elevations. Over the past week, there was a well-documented wet avalanche cycle that likely started on the 24th and continued at least through the afternoon of the 26th. Many wet slides ran on a range of slopes, and some deeper slab avalanches were reported up to D3.

Before warming and rain, the January Drought Layer was buried 2–3.5 ft and shallower east of Mazama. Near Rainy and Easy Passes, the JDL was over 4 feet deep and capped with a thick melt-freeze crust. On March 17, an observer near Tiffany Mountain reported widely propagating recent natural avalanches and rolling collapses on a weak layer in the middle to lower half of the snowpack. As observations have become limited, our uncertainty about the snowpack has increased.

Submit an observation to the website or the Avy App to help NWAC Forecasters reduce uncertainty. It can be short, simple, and even anonymous. 

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