Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

With increasing winds overnight and tomorrow, you may be able to trigger avalanches in wind-drifted snow on steep slopes below ridges, confined terrain features, and at the base of cliffs. Steer around steep slopes with stiff, textured snow drifts. In the western edge of the zone, the higher recent snow totals mean more snow is available to drift, and avalanches could be larger.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Ridgeline winds will pick up overnight and may sustain in the moderate range throughout the day on Saturday. Some areas have limited available snow for transport, but areas near the crest and upper elevations likely have enough soft snow to build new shallow wind slabs on lee slopes.The most likely locations to trigger avalanches will be steep slopes below corniced ridges. Also, look for specific terrain features such as the base of cliffs or confined chutes and gullies as prime trigger points. There is a possibility that wind slabs could step down into deeper buried weak layers. This scenario would produce a much larger, surprising avalanche that could be unsurvivable. This problem is particularly concerning in areas near and around Stevens Pass. Although uncertainty exists, similar conditions could also linger in areas further east. With this increased uncertainty, travel with a conservative mindset and consider wider safety margins.

    Use visual clues such as textured surfaces and drifts around rocks and trees to identify wind slabs. You can also use your probe or pole to feel for stiffer snow over softer snow layers and use quick hand pits to observe how easily the wind-stiffened snow slides off deeper soft layers. If the surface snow slides easily or you see other signs of instability, such as shooting cracks, steer around these wind-stiffened drifts in steep terrain. 

    (1/5/2023)

    Confined terrain features on steep slopes below ridges, like in this photo, are possible locations to trigger wind slabs. 

    Photo: NWAC Public obs

Avalanche Discussion

On Friday, forecaster, Matt Primomo,  went to the White Pine drainage at the western edge of the zone and found up to 3" of new snow and fresh drifts up to 20cm near treeline. On Thursday, forecaster, Katie Warren, traveled in the Salmon La Sac area to ground truth this week's storm totals and investigate the bond between the most recent crust and the new snow. Warm temperatures from last week created a strong crust at lower elevations. Above 4500ft in open terrain, Katie found new snow accumulation of 1 foot. The new snow was well bonded with the crust, although some weak snow exists beneath this recent crust (2/12) and will be an interface to watch as we go into a stormy period next week. The MLK crust is around 2.5ft deep, and the Christmas crust is down 3-4ft in this area.  In the nearby Stevens Pass zone last week, there were large avalanches with wide propagation, potentially on buried weak layers resting over stout crusts. These avalanche occurrences are worth noting if you plan to travel along the East-Central zone's western edges. You should consider the high consequences of triggering a larger and more surprising avalanche. With enough snow, next week's storms could produce similar avalanches in the East Central, but we'll have to watch as conditions evolve.

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