Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

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

The chance of triggering large and surprising avalanches on deeper weak layers is maintaining Moderate avalanche danger. You may be able to trigger avalanches more easily near Harts Pass and in the northeast portion of the zone. For Friday, expect increasing clouds, warming temperatures, and a chance for light snow or possibly rain at low elevations. 

Avalanche problems

  • Deep Persistent Slabs

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

    In much of the zone, avalanches are difficult to trigger but not impossible. You may be able to trigger them more easily near Harts Pass or where the weak layer is close to the surface.  Deep Persistent Slab avalanches could easily be big enough to kill you and could even be unsurvivable. Limit your exposure to large start zones. Avoid complex and unsupported terrain, shallow, rocky areas, and unsupported slopes.

    On March 3rd and 9th, backcountry travelers in the Harts Pass area triggered large to very large avalanches on northerly aspects near treeline. You can find the late January weak layer (facets sandwiched between two crusts) 3-5' below the surface. Snowpack tests can help you identify the layer of concern. Sudden or propagating results have remained consistent during periods when avalanches have become difficult to trigger. East of Washington Pass, the snowpack becomes shallower, and this interface may be nearer to the snow surface.

    (3/3/2022)

    A very large (D2.5) and widely propagating slab avalanche was triggered by a snowmobile on March 3rd. The crown is estimated at roughly 5ft deep. 6600-6800ft, NE, near Harts Pass

    Photo: Drew Lovell

Avalanche Discussion

On March 9th, observers near Harts Pass remotely triggered a sized R3-D2 avalanche from 20-30 feet away. The avalanche occurred roughly around 6,600ft on a north aspect. On March 3rd, a similar size D2.5 avalanche was triggered nearby on Tatie Peak on a northeast aspect at 6,800ft. Fortunately, no one was caught in these avalanches. Observers reported other deep crowns in the Hairpin Valley and near Azurite Pass after an avalanche cycle on 2/28-3/1. This is evidence that the late January facets could produce more avalanches under the right conditions.

You could find some thin and older drifted slabs above treeline. Travel conditions may be challenging, especially at lower elevations where you'll find plenty of firm avalanche debris and crusts from the storm and associated avalanche cycleat the beginning of March. The rain formed a crust up to 5,500- 6,500ft depending on location.  Widespread avalanches occurred in storm instabilities as well as deeper old, weak layers. Observers report both wet and dry avalanches, with most occuring in new snow instabilities and a handful running on deeper layers.

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