Lawinenlagebericht

West Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Snow conditions will dictate the avalanche problem you’re dealing with. Steer clear of steep slopes where the snow is becoming wet and heavy, or where you’re seeing rollerballs, pinwheels, or small wet avalanches. In drier snow, long shooting cracks are a strong warning sign that slab avalanches are possible on steep terrain.

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Moderate snowfall combined with rising temperatures sets the stage for storm slabs to develop over slightly softer, weaker snow below. Expect slab reactivity to increase through the day, with peak instability in the afternoon. If snowfall amounts exceed the forecast, expect greater danger at mid elevations as well.

    You’re most likely to trigger a slab on leeward slopes loaded with wind-drifted snow, or during periods of heavier snowfall. Use small test slopes and hand pits to assess how new and wind-drifted snow layers are bonding. Stomping on wind-drifted features, such as small cornices or wind lips, can also help you evaluate wind-loaded slopes.

    Use small, wind-drffted features for slope tests.

    Photo: Jason Speer - Baker Mountain Guides

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Rising snow levels will likely lead to an uptick in wet avalanche activity, especially where fresh snowfall is followed by warming temperatures or rain. Wet avalanches are most common below steep rocky headwalls and cliffs, but could also be triggered on any steep slope. If temperatures run warmer than forecast, wet avalanche activity may also extend into higher elevations. Low elevations should see few avalanches, as nearly no snow has accumulated there in the last five days.

    Pinwheels are a sign the snow  surface is warming up.

    Photo: Zack McGill - Cascade Mountain Ascents

Avalanche Discussion

Observers have reported a smattering of avalanche activity in zones neighboring West Central, including a mix of small slab and wet loose avalanches. The most notable was a cornice release and subsequent slab avalanche in West North that coincided with the onset of light rainfall on Saturday. Overall, alternating periods of colder snowfall, rising snow levels, and rain have led to rapid fluctuations in stability.

Between 3 and 6 inches of moist new snow have fallen along the west slopes of the Cascades over the past 24 hours. At mid elevations, the new snow was generally too moist to support much wind transport or slab formation. Conditions were likely different at upper elevations, where stronger winds and colder, drier snow prevailed. Poor weather and limited visibility kept most travelers out of the alpine, leaving no observations from higher terrain.

Looking ahead, temperatures are forecast to continue climbing, with freezing levels reaching 9,000 feet or higher by Tuesday afternoon. Periods of full sun are also expected. While not a certainty, there is a good chance of larger and longer-running wet avalanches, especially at upper elevations that have received many feet of new snow over the past five days.

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