Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Avalanches in wind-drifted snow and wet avalanches on sunny slopes will be the most likely problems on Tuesday. Steer around steep terrain below ridgelines and move to shady or lower-angle slopes if the snow becomes wet and heavy. Avoid steep north aspects where there is a chance of triggering a very large, consequential avalanche on old snow layers. 

Avalanche problems

  • Wind Slabs

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

    Older wind slabs are gaining strength, but fresh wind drifting could form shallow new slabs overnight. The most likely place to trigger a wind slab is steep, unsupported slopes at upper elevations, especially in confined gullies. Look for cornice formations and pillowlike drifts, or feel for stiffer snow layers to identify wind-affected terrain. Cracks shooting out from your equipment or recent avalanches are signs to avoid steep terrain. You can also use small wind-affected test slopes to see how the snow reacts, if the snow fractures and slides easily, avalanches are more likely. Smaller storm slabs or loose snow avalanches are possible in sheltered terrain.

    A smaller wind slab might step down to more deeply buried weak layers, becoming a very large and dangerous avalanche. 

    (11/26/2024)

    Example of shooting cracks in wind-textured snow. 

    Photo: Will Govus

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    It won't take much time for the intense March sun to make wet avalanches possible on steep sunny slopes. Pay attention to overhead hazards from snow shedding off steep rocks and move to lower-angle terrain if you begin to see rollerballs or the snow feels wet and sticky. You might be more likely to trigger these avalanches where new snow rests over slick crusts. 

    There is some uncertainty with the cloud forecast, so if there are more clouds, wet loose avalanches are less likely. If it's a full bluebird day, expect more widespread and larger wet loose avalanches. 

    (12/4/2024)

    An example of wet loose avalanches that started from steep rocks shedding snow onto the slope below.

    Photo: Drew Lovell

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    With this low likelihood, high consequence situation, continue avoiding steep northerly slopes where you could trigger one of these very large avalanches. They may be easier to trigger near exposed rocks or on wind-loaded slopes. Persistent slabs take a long time to gain strength and require patience along with careful decision-making. 

    We expect this problem to be more likely further north and east in the forecast area. But with significant uncertainty, it's best to focus on the potential consequences and continue to travel conservatively. You may not receive any of the typical warning signs, like collapsing before triggering a slide, and these avalanches could be unsurvivable, breaking across entire slopes and running long distances.  In two separate involvements in late February near Harts Pass, snowmobilers were buried, and one person was killed. More recently, observers in this area found test results showing that the weak layer still has the potential to fail and propagate. Further east, near Tiffany Mountain, an observer reported widespread collapsing and recent large, widely propagating avalanches.

    (2/28/2025)

    A large avalanche near Hart's Pass that caught 2 snowmobilers and resulted in one fatality on February 28th. 

    HS-AM-D2.5-R4-O. Cone Mtn, NE, 6,800ft

    Photo: NCH

Avalanche Discussion

Tuesday could be the sunniest day of the weak, with light to moderate winds. Ambient temperatures will be chilly, but the mid-March sun will feel warm if it makes a prolonged appearance. 

Recent storm totals are between 1-2ft but taper quickly to less than 1ft further east in the zone. Observers continue to report natural and triggered small wind slabs at upper elevations. Lower elevations have a thin melt-freeze crust that softened in the afternoon on Sunday. 

A late February storm brought 18" of snow to the area and was followed by prolonged warm weather into early March. This resulted in a widespread natural avalanche cycle, first persistent slabs, and then wet loose and wet slab avalanches. Observers reported many large to very large avalanches with widely propagating crowns. The weak layer (January Drought Layer) is buried 2–3.5 ft (70-120cm) below the surface near Washington Pass, but much shallower further east and north. Near Rainy and Easy Passes, the JDL is over 4 feet deep and capped with a thick melt-freeze crust. Over the weekend, observers near Harts Pass reported large and small column tests indicating that propagation is likely on the January Drought Layer. Another observer near Tiffany Mountain reported collapsing and a suspiciously large avalanche. We believe this problem is more likely in these areas with a shallow and weaker snowpack. 

NWAC Forecasters visited the site of the avalanche fatality near Harts Pass that occurred on 2/28. You can read the initial observation here. 

You can help us gather more data by submitting an observation HERE or via the Avy App. 

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