Bulletin d’avalanche

West Slopes South

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

If you’re out enjoying the generally nice day on Monday, take note of visual clues such as textured surfaces from the recent windy weather. They can help you locate wind-loaded features for you to steer around as you ascend in elevation.  Slabs may exist in some unusual locations or on a variety of aspects due to easterly winds.

Problèmes avalancheux

  • Wind Slabs

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

    You may still be able to find reactive Wind Slabs on Monday at mid to upper elevations throughout the zone. Atypical easterly winds on Sunday easily transported snow into unstable piles near ridgelines as well as mid-slope. You can use visual clues such as textured surfaces, newly built cornices, or drifts behind objects to determine which way the wind may have been transporting the snow. Then you can look for pillow-like drifts where the snow looks “fat” to identify wind-loaded features to steer around. They may be on different aspects or further off the ridge than you're used to seeing them. Using small test slopes as you travel can give you an indication of how the wind-drifted snow may be reacting to your weight. Near ridgelines, some of these slabs may be firm and feel hollow, indicating a hard slab. Don’t mess with these ones, they can break in unpredictable ways, including above you.

    (1/29/2023)

    This NE-E facing blowing is normally full of snow, but with this wind pattern, it is stripped down to old crust layers.

    Photo: Dallas Glass

Avalanche Discussion

The West South is a huge zone, leading to a divergence in conditions from time to time. Due to variable snow accumulations on Saturday and that snow’s exposure to wind on Sunday, you may find slabs with different depths and reactivity based on your location on Monday. That said, the travel advice and general management stay true no matter where you recreate. You’re most likely to trigger an avalanche in wind-loaded terrain - the size and consequences of such an avalanche are what may vary.

Sunday was a gorgeous but chilly and breezy day around the zone. Avalanche professionals near White Pass reported copious amounts of blowing snow, Wind Slabs on a variety of aspects, and plenty of visual clues to help identify that the wind had been a player. A few small avalanches were triggered by skiers in wind-loaded terrain at mid-elevations. We do not have any observations from anywhere else in the zone at this time. NWAC weather stations indicate the volcanoes likely picked up close to a foot of snow during this event, White Pass picked up 5-6 inches,  and areas near Chinook Pass and Crystal Mountain got basically nothing. Winds were moderate with some strong gusts at most stations on Sunday.

We anticipate continued cold temperatures and clear skies to start the day on Monday. Be sure to bundle up out there. As the day progresses, temps should start to moderate while cloud cover increases. Even though we still have our eye on some deeper layers above the MLK crust, any avalanche activity on Monday should be confined to the recent snow above the 1/27 interface.

Régions couvertes