Avalanche forecast

West Slopes South

Northwest Avalanche Center
View on map

Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Dynamic spring weather could cause a variety of generally small avalanche issues on Tuesday. At higher elevations, the danger should be confined to wind-loaded areas. As the sun comes out, you could see natural wet avalanches, particularly near rocky faces. Conditions may be the most dangerous on Mt St Helens and Mt Adams, where more snow is expected.

Avalanche problems

  • Wind Slabs

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

    Look out for places where the wind drifted the recent snow into slightly deeper pockets. You could see these along exposed ridges at upper elevations, near the base of cliffs, or in the tops of chutes. Blowing snow, textured surfaces, and sharp drifts all point toward potential wind slabs. Be leery of firmer pillow-like drifts in steep terrain. Don’t let one of these shallow avalanches push you over a cliff or into a rock. 

    Wind slabs should be the largest and most dangerous on the volcanoes where there’s more recent snow to help build these slabs.

    This wind slab avalanche was triggered on Mt St Helens on Sunday. (3/24/2024) Photo: Alex M

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    You may trigger a very small wet loose slide near the rain-snow line in the morning. However, our worry is more about when the sun comes out. It doesn’t need to be full blue skies; even filtered sunshine can help temperatures quickly spike. If this happens, natural wet avalanches may follow. Snow falling out of trees and new rollerballs all show the scales tipping. 

    These natural slides should be mostly confined to rocky terrain receiving direct sunshine. Pay attention to the slopes above you, and don’t hang out underneath cliffs and other very steep sunny slopes. In some cases, blocks of snow may shed off these slopes and produce large, more dangerous avalanches.

    (3/18/2024)

    A skier-triggered wet loose avalanche that entrained snow as it gouged into older layers. 

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

Mt St Helens and Mt Adams are much closer to the action with this storm and should receive more precipitation. Expect more dangerous conditions in these areas. The Mt Hood forecast may provide additional details. 

A weak frontal system will bring a bit more precipitation to the West South zone Monday night and Tuesday morning. Expected snow totals aren’t impressive. Areas near the Crest could receive 2-4 inches, with 4-8 inches on the volcanoes.

This adds to the modest snowfall amounts since 3/20. Below this recent snow a new crust formed. This firm layer is helping alleviate concerns about older deeper weak layers in the snowpack. You can still find facets on and near the Early February Crust, but these layers significantly gain strength. It would likely take a very large trigger in rocky complex shaded terrain to still produce a slide. 

The lower elevation snowpack took a huge hit during the recent warm weather. Expect shallow coverage, open creeks, and lots of tree debris. Not much, if any, new snow accumulated below 4500 feet around the zone.

Regions covered