Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Fri
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

Limit travel on or directly under steep slopes seeing direct sun or where the snow is mushy and wet. Avoid this terrain if you see signs of instability like rollerballs and recent avalanches. Steer around steep terrain at upper elevations that holds dry, wind-drifted snow.

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Thursday isn’t forecast to be full bluebird. But there could be enough sun - along with continued mild temperatures -  that more wet avalanches are possible. As usual, the extent of wet avalanche activity will hinge on cloud cover, temperature, and the snow surface in each area of the forecast zone. 

    With temperatures and wet new snow, observers reported plenty of wet avalanche activity on all aspects at mid-elevations on Wednesday. Look for additional avalanches in sun-exposed, upper-elevation slopes still holding cold snow that can react to sun and warming.

    (2/21/2024)

    A natural wet loose avalanche initiating from steep, rocky terrain on the south side of Mazama Dome/West North at about 5500'.

    Photo: Zack McGill - Cascade Mountain Ascents

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Dry snow might actually exist in alpine terrain. Be ready to assess the stability of new and wind-drifted snow layers if you get that high. While you are more likely to trigger an avalanche on wind-drifted slopes, there is enough new snow that slab avalanches could also occur in wind-sheltered areas

    Track the depth and stiffness of new snow layers as you gain elevation. Visual clues can also help you identify areas with thicker slabs, but a bit of fresh snow falling overnight might make scoured slopes and pillowy-looking wind drifts harder to see.

    (2/24/2022)

    Stiff snow that cracks when weighted means you found an unstable wind slab.

    Photo: Adam Ü

Avalanche Discussion

Observers along the west slopes reported another wet day. Widespread rollerballs but no fresh avalanches were noted at Snoqualmie Pass. In West North, multiple wet loose avalanches occurred naturally on all aspects at mid-elevations in the Baker BC. “Dry is not a word I would use to describe any part of our ski day” might be the best summary of current conditions.

West Central appears to have been on the low side for precipitation, while zones to the north and south saw quite a bit more. Most West Central weather stations recorded about a quarter-inch of precipitation since Tuesday afternoon. Snoqualmie Pass and Stevens received roughly the same. Precipitation generally fell as rain or very wet snow at low and mid-elevations. 

The thick rain curst buried in early February can be found anywhere from near the surface to 2-3' down, depending on elevation, aspect, and exposure to sun and wind. Weak, faceted snow was found above this crust and at other layer interfaces over the past few weeks, but has generally been observed as rounding and gaining strength in this forecast zone. 

Régions couvertes