Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Warming temperatures and another shot of snow may lead to storm slabs and loose avalanches that become easier to trigger during the course of the day. Stay atuned to the surface conditions and signs of instability like shooting cracks, sluffing, or moist snow that entrains. Identify steep, unsupported and consequential slopes to steer clear of if you find these.

Avalanche problems

  • Storm Slabs

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

    At upper elevations where more new, dry snow may fall, check and see how it reacts on steep slopes. Slabs could be more reactive in areas of fresh wind loading, and with warming temperatures we may see an 'upside down' storm layer. Loose dry 'sluffs' may run easily on the crust from Wednesday. You can evaluate how well the new snow is bonding with simple tests like slope cuts, skin track tests, and hand shears.

    If you find signs of instabilities like shooting cracks or easy failures with practical tests, than steer away from large, steep, unsupported or consequential slopes.

    Example shallow but fairly wide natural soft slab in Rock Mountain's East Bowl.

    Photo: Matt Primomo

  • Loose Wet

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

    You might find 3-8" of new snow over a new crust from the recent warmup. This could create a good surface for that new snow to slide on once snow levels bump up in the afternoon.

    Wet slides often start from trees or rocks shedding snow onto slopes below, but you can also trigger them with your skis or snowmobile. Look for signs of instability that include rollerballs, or fresh wet slides. Identify steep features that warrant caution, and keep checking in to see how conditions are changing throughout the day. You wouldn't want to get dragged down in a steep ravine or into trees in one of these.

    Example of a small wet loose avalanche. 

    Photo: Matt Primomo

Avalanche Discussion

The pass picked up 3-5" of new snow on Wednesday. An observer reported a large whumphing collapse on a southerly aspect near Rainy Pass on Wednesday. At SPMR, snow safety reported small sluffs running on the new crust (1/24) with ski triggering. A widespread wet loose cycle occurred on Wednesday with light rain falling on the previously dry snowpack. These ran in the D1-1.5 range, but a handful were D2's (Lichtenberg), and perhaps one D2.5 (West Camp on S side of Rock Mtn).

Some very large avalanches ran on deeper weak layers within the Solstice Crust sandwich earlier in the month. Regionally, a very large slides have been triggered on a similar old crust layer at Mission Ridge on Wednesday, and Crystal Mountain on Tuesday (see photo). This crust and facet complex is now 4-5 feet below the surface in much of the zone. Last week snowpack tests had given sudden and propagating results, and although at the moment this layer is considered dormant in the zone, things may be starting to change as more snow accumulates. If you venture to the eastern half of the zone, it would be worth reading the East Central forecast. If you make it out, please share what you found with an observation.

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