Bulletin d’avalanche

West Slopes South

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Strong winds, periods of heavy precipitation, and warming temperatures could creat dangerous avalanche conditions, particularly Monday afternoon as the storm intensifies and snow totals stack up. Avoid steep open slopes at all elevations.

Problèmes avalancheux

  • Storm Slabs

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

    The exact type of slab problem you encounter will depend on your location and how much new snow you receive. In the morning and for areas close to the crest, the primary hazard could come from wind-loaded slopes. Near the volcanoes and later in the day, you may see the problem spread to nearly all steep open areas. 

    You’ll need to monitor the dynamic conditions of the day and be ready to respond by dialing back your terrain selection. Choose plans with lots of options, including easy safe routes back to your car. 

    Use small test slopes, up-track tests, and hand pits to look at how the snow responds to your weight. If you see cracks or small avalanches, stay off of open areas greater than 35 degrees. Near ridge crest and on exposed features, be suspicious of any wind-loaded slope. Blowing snow should easily help you identify these locations. Slabs in these areas could be more than a foot thick and break above you. 

  • Loose Wet

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

    Near and below the rain-snow line you’ll probably see natural loose wet avalanches. Fortunately, they should be easy to anticipate and manage. New rollerballs and point-release slides are telltale signs that more natural avalanches are likely on similar slopes. When you see these clues, limit the time you spend on or under this terrain. 

    While most of these avalanches should stay small, on longer slopes you may see some slides grow large and potentially deadly.

    (1/14/2023)

    Example: You could see wet slides like this at lower elevaitons Monday. NW aspect ~4300'

    Photo: NPS Rainier Rangers

Avalanche Discussion

Just because the West South zone isn’t flashing red like our neighboring zones to the north, don’t assume it’s safe. Conditions could still become dangerous, especially near Mt Rainier and Mt St Helens later in the day. In areas that see less than 6” of new snow, you’ll probably only encounter Moderate hazard. This storm should finally push into the West South Monday afternoon and cause avalanche danger to increase dramatically overnight. 

Observations from this weekend indicate that the upper snowpack is generally strong and should handle the new snow loads well. While we can easily find the 2/17 and 2/13 layers, we expect most avalanches to occur at or above the new/old interface. That said, we won’t be surprised to hear of a few isolated slides down to these slightly older snow layers, particularly if rain reaches higher into the mountains than expected. 

Observations from Paradise and White Pass on Sunday indicated windy weather with plenty of blowing snow. Warm temperatures, thin clouds, and even some unexpected sunshine resulted in a barrage of new rollerballs and a few small loose wet slides on steep sunny slopes.

Régions couvertes