Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Warming temperatures and complex avalanche conditions mean you should keep your distance from and stay out from under large, steep slopes where avalanches could start, run, or stop. Expect natural and triggered wet avalanches on steep, sunny slopes. You may be able to trigger dangerous slab avalanches from far away or where the wind has drifted recent snow. 

Avalanche problems

  • Persistent Slabs

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

    You can trigger dangerous persistent slab avalanches on slopes 35 degrees and steeper. You may be able to trigger these avalanches from far away or from overhead slopes. Avoid being on or under suspect slopes, especially where you see fresh drifts. Use extra caution on slopes that hold fresh drifts from westerly winds on Friday night. Put a large buffer of terrain between where you travel and large start zones. Minimize your exposure to large avalanche paths and look for safe locations to stop or regroup.

    "Red flag" signs of the danger include whumphing collapses, cracks shooting through the snow, and tests that propagate or fail suddenly. The late-January weak layer can be found 1.5-2 feet below the surface and is a combination of weak, sugar-like facets and crusts. You may find the weakest snow sandwiched between two crusts. At mid-elevations, about 5,300-5,600ft, you can find buried surface hoar at this interface. We have good information about the problem near Washington Pass and Hart's Pass. We believe that the problem exists elsewhere in the zone, though we have less information about the nature of it there. 

    (2/4/2022)

    A party remotely triggered avalanche (R4-D1.5) from 600 feet away in the Hart's Pass area. This avalanche sympathetically triggered another small slide nearby. East, 6,800ft.

    Photo: Josh Cole

  • Wind Slabs

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

    Moderate to strong westerly winds formed shallow slabs on leeward sides of ridges Friday into Saturday. While you can keep from triggering these small avalanches by steering around the drifts, you could trigger much more deadly persistent slab avalanches on many of the same slopes. This recent snow could be enough to overload deeper weak layers. To stay safe, you will need to avoid both the wind slab and persistent slab avalanches.

    (2/5/2022)

    Small skier triggered (D1.5) wind slab avalanche in new snow near Table Mtn in the neighboring West North zone.

    Photo: NWAC Public Obs

  • Loose Wet

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

    Natural wet avalanches are most likely on east through south through west aspects and triggering is likely there as well. You may even be able to trigger these avalanches on shadier aspects, though they'll be small. There's enough soft snow near the surface that wet avalanches could be big enough to injure you or push you into trees or rocks. Rollerballs, snow falling from trees, and fresh avalanches are all signs that you should move to more shaded or lower-angled terrain. The very warm temperatures and plenty of natural wet avalanches are maintaining concern for triggering old weak layers buried well below the surface. 

    (1/26/2022) Examples of wet avalanches from a range of dates between Jan 12-22th. SE-NE, Whistler Mtn and Cutthroat Peak Photo: Josh Hirshberg

Avalanche Discussion

Conditions are complex with multiple overlapping avalanche problems. You can manage the risk by limiting your exposure to avalanche terrain- stick to lower-angled slopes and simpler terrain. On Saturday, observers reported a number of natural and triggered avalanches in newly drifted snow up to size D1.5. Since earlier in the week, observers have reported numerous signs of instability including triggered avalanches, collapsing, and tests showing the potential for triggering slides on the late January facet/crust layer. Another observer, on Kangaroo Ridge, also reported collapses in mid-elevation terrain and sudden test results on the late-Jan weak layer at 6,600ft, SW. Plenty of warning signs show that we're dealing with dangerous and complicated avalanche conditions.

Avalanche observations: On Saturday, professionals intentionally triggered small wind slab avalanche on east through south aspects above treeline near the Lyall glacier. Observers reported natural wind slab avalanches in the Hairpin Valley and on an east aspect, near treeline on Cutthroat peak. We received a report of backcountry travelers involved in a triggered avalanche near Maple and Heather passes with few other details. See photo below. Saturday was also an active day in the neighboring West North zone, where backcountry travelers triggered both wind slabs and large persistent slab avalanches (see photo below) on the same late-January weak layer that exists in this zone. On Friday, observers reported remotely triggering a slab avalanche (size R4-D1.5) from approximately 600ft away on an east aspect near 6,800ft in the Hart's Pass areas. This slide triggered another (sympathetic) small slab avalanche. 

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