Avalanche forecast

West Slopes South

Northwest Avalanche Center
View on map

Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A huge swing in the weather will create a very complex, dynamic, and uncertain set of avalanche issues on Friday. On some slopes, natural avalanches could occur. Get ready to adapt to changing conditions.

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    This big change in the weather only adds another layer of uncertainty for this problem. The potential for natural avalanches and cornice falls could trigger a few isolated very large slides. With the weak structure present all across the zone, it’s really hard to say when and where they could occur. 

    Facets continue to persist within the Solistice Crust. They resulted in numerous avalanches over the past few weeks. While this layer has been quiet lately, give it some space through this warm-up. Discuss the higher uncertainty and consequences of this problem before entering bigger terrain.

    (1/10/2024)

    Very large avalanche on North Peak at White Pass Ski Area

    Photo: White Pass Ski Patrol

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    In some places, there’s very little new snow, in others, there’s a lot. You may trigger avalanches within or at the bottom of the storm snow (1/16 interface). With more snow expected Thursday night, these slabs should be easiest to trigger first thing in the morning. Near surface facets and surface hoar were reported prior to this storm. Avalanches failing on these weak grains might trigger easily or even remotely. 

    Hand pits, small slopes, and up track tests can all help you see how the new snow will reach. However, make sure you look all the way down to the base of the new snow (1-2.5ft, 30-75cm). In places that start to warm, these surface slabs could change dramatically.

    (1/6/2024)

    Example: Even small slopes like this could avalanche within the new snow. 

    Photo: Andy Harrington

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    The warm-up is most certain west of the Crest for places like Mt Rainier and Mt St Helens. However, you could see higher temperatures and/or rain even near Crystal. If you start noticing it getting warm and muggy, pay attention. Snow shedding from trees and rollerballs will let you know the scales are tipping to “wet.” 

    This event could just be a few rollerballs and some heavy snow, or it could unleash a barrage of wet loose slides. When you see avalanches, dial it back and limit any time you spend on or near steep slopes.

    Example: (4/7/2023) Piles of rollerballs like this indicate the snow surface is becoming wet and unstable. Photo: Dallas Glass

Avalanche Discussion

The forecast for the next 24hrs is messy, complex, and uncertain. We very rarely issue forecasts with 3 avalanche problems. The only way to really sum it up, is a big change is in store for the mountains.

Places like White and Chinook Passes could see easterly flow stave off the warm-up. Or, a layer of freezing rain might cap the snow in ice and all but eliminate avalanche issues. Near Crystal, less recent snow and a propensity to stay a bit colder could result in a slightly lower hazard. However, the bulk of the persistent slab activity occurred there. 

At this point, you get it. Things are a bit of a coin flip. “When uncertainty goes up, terrain goes down." seems like sage advice. Make sure your trip plan allows you to easily adjust and provides a simple safe way home if more dangerous conditions develop.

Regions covered