Bulletin d’avalanche

West Slopes South

Northwest Avalanche Center
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Danger d’avalanche

Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Nothing gets winter lovers excited like an incoming storm. An atypical wind direction and new snow could result in wind slabs forming in unusual locations. The highest danger will exist on the southern volcanoes where the storm strikes first. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Fresh slabs could develop on specific terrain features such as rocky chutes or convexities as the storm moves northward on Wednesday. Easterly winds often result in more cross-loading and mid-slope loading than you might be used to. They also load different aspects than our typical storms. Look for actively blowing snow or new drifts to identify wind-loaded features to avoid. You can use small test slopes to check the reactivity of the new snow.

    (2/12/2024)

    Fresh cornices and drifts help indicate that wind slabs may exist on leeward slopes.

    Photo: Dallas Glass

Avalanche Discussion

We’re heading into a colder and snowier storm after a few days of reasonably warm weather around the zone. This system is traveling from south to north, meaning Mount St. Helens and Mt. Adams will get into the snow action first. Other areas of the zone will mainly deal with an east wind event on Wednesday, with snow showers arriving later in the day. 

New snow will be falling on a variety of surfaces. You will likely find well-settled powder interspersed with weak snow grains on shaded slopes, including on top of the Early February Crust (EFC). On sun-exposed slopes, you’ll discover crust sandwiches or a thicker EFC. Most aspects have seen at least some warming over the last few days and will likely develop a new surface crust on Tuesday evening. 

Avalanche professionals reported widespread surface hoar on Tuesday that could persist on sun and wind-sheltered slopes. This could result in a few surprising avalanches over the next few days. You could also see failures at the 2/11 interface or the EFC (1.5-2 feet below the surface). We do not expect any avalanche activity below the EFC during this event.

Lower elevations contain few avalanche problems, but travel can be difficult. You’ll likely need to navigate slick crusts, open creeks, exposed rocks, and refrozen avalanche debris.

Régions couvertes