Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Moderate to strong winds will combat rising temperatures and sunshine to determine avalanche potential on Sunday. Be cautious of slopes where you see actively blowing snow or find a wet, soggy surface. You may want to limit the amount of time you spend traveling below overhead hazards such as cornices or glide cracks.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1

    East winds are expected to intensify throughout the zone. They'll be easily strong enough to drift recent snow into slabs on leeward slopes. Look for actively blowing snow, fresh cornices, or new pillow-like drifts to help identify wind-loaded features to avoid. Since the wind is coming from the east, you may find slabs form on atypical aspects or locations, such as mid-slope. Although there may not be a lot of dry snow available for transport, there should be enough to consider this problem, especially on the volcanoes. Slabs should be resting on a newly formed crust, which could act as a good bed surface for avalanches to run far distances.

    (3/29/2025)

    A recent wind slab avalanche on a relatively small slope in the Mount Adams area was spotted by sledders on 3/29. [SE 7800']

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    It's springtime, so we can't escape wet avalanche problems. Temperatures and sunshine are forecast to increase on Sunday, which could lead to wet loose slides in the new snow. This is a different problem than the large and devastating wet slabs we've been discussing for several days - more on those in the discussion. What you're going to want to watch out for here are slopes basking in the sun. The surface snow could destabilize, resulting in new rollerballs, pinwheels, or fan-shaped avalanche debris. Much like the wind slab problem, there is an underlying crust, so these slides have the potential to travel long distances, grow in size, and fan out as they descend. 

    (3/29/2025)

    The new snow got moist on Saturday on sun-exposed slopes, resulting in rollerballs and other wet loose activity.

    Photo: Rachel Gronvold

Avalanche Discussion

We're in full springtime forecasting mode in the West South zone. Sunday will be a prime example. We've just received some new snow, and now the sun should emerge, along with a slight increase in temperatures, as we experience a brief respite between weather systems. This should open the door for wet avalanche problems. Of course, competing factors like strong easterly winds and increasing cloud cover throughout the day may not allow the wet problems to materialize. So, keep an eye on the sky and notice how the snow surface is changing throughout the day to help identify your primary avalanche concern.

Observations from Saturday indicate that at the base of the recent storm snow, our wet and weak snowpack is forming a thick crust. That should help limit those deeper and scarier wet slab avalanches we've experienced for much of the last week. Does that mean that they're impossible? Definitely not. We wouldn't be surprised to hear of a very large avalanche occurring. However, we don't think it's very likely at this point; otherwise, we'd still have it on the official problem list. Still, you may need to contend with some sagging cornices or other blocks of snow falling off rocky ledges in isolated locations. Consider limiting the amount of time you spend traveling below areas where slides like this could occur. 

This week's wet avalanche cycle has resulted in very large slides at Mount St. Helens, Mount Rainier, The White Pass area, and Crystal Mountain. That covers most of our major information sources. The landscape is now littered with avalanche debris. Some may be hidden under the fresh snow. Holes, creeks, open water, and bare ground have all been exposed. When planning your day, allow extra time to navigate these hazards.

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