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Due to recent storm damage, the access road to the northern trailhead is closed until further notice. Please use alternate routes.

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West Slopes South

Backcountry Avalanche Forecast

This is an archived product. View the most recent forecast or all archived forecasts.

Author: Sam Clairmont

Issued: Friday, April 17, 2026 at 6:30 PM PDT

Expires: Saturday, April 18, 2026 at 6:30 PM PDT

The Bottom Line

Spring-like weather continues, with larger temperature swings and variable snow and avalanche conditions. Wet avalanche activity will be front and center as the day heats up, but areas of wind-loaded snow may still exist as well. Remain flexible on travel plans, and move to simpler, lower-angle terrain as the day heats up.

Avalanche Danger

Saturday, April 18, 2026

Upper Elevations
8000-6500ft
2 - ModerateModerate
Middle Elevations
6500-5500ft
2 - ModerateModerate
Lower Elevations
5500-3500ft
2 - ModerateModerate

Sunday, April 19, 2026

Upper Elevations
8000-6500ft
2 - ModerateModerate
Middle Elevations
6500-5500ft
2 - ModerateModerate
Lower Elevations
5500-3500ft
2 - ModerateModerate
Elevation Band Descriptions
Avalanche Danger ScaleLearn moreGeneral Info1 - Low2 - Mod3 - Cons4 - High5 - Extr
Low
1 - Low
Moderate
2 - Moderate
Considerable
3 - Considerable
High
4 - High
Extreme
5 - Extreme
Travel AdviceGenerally safe avalanche conditions. Watch for unstable snow on isolated terrain features.Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of AvalanchesNatural and human-triggered avalanches unlikely.Natural avalanches unlikely; human-triggered avalanches possible.Natural avalanches possible; human-triggered avalanches likely.Natural avalanches likely; human-triggered avalanches very likely.Natural and human-triggered avalanches certain.
Avalanche Size and DistributionSmall avalanches in isolated areas or extreme terrain.Small avalanches in specific areas; or large avalanches in isolated areas.Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.Large avalanches in many areas; or very large avalanches in specific areas.Very large avalanches in many areas.

Avalanche Problems (2)

Problem #1: Wet Loose

Problem Type
Wet Loose
Aspect/Elevation
NNEESESSWWNW
Likelihood
CertainVery LikelyLikelyPossibleUnlikely
Size
Historic (D4-5)Very Large (D3)Large (D2)Small (D1)
(4/5/2026)

Intentionally triggered wet loose avalanche in the West South zone.  Slides like this often occur when the surface becomes wet and weak. 

Video: Sam Clairmont

Temperatures won’t cool as much overnight, followed by warmer conditions on Saturday. Continued warming will keep the possibility of wet avalanche activity, especially late in the day. As surfaces soften, you might be able to trigger avalanches on steep slopes, particularly on sun-exposed aspects, but shaded slopes may also become reactive. In rocky and complex terrain, snow may still shed naturally.

Warm, unstable snow will first show on sunny slopes as roller balls, snow shedding from rocks and cliffs, or small natural or human-triggered avalanches. As the day warms, keep an eye out for these early signs. You can also use small convex test slopes to test how easy it is to initiate a wet avalanche. Once you start to notice these indicators, shift to more supportable snow or to lower-angle slopes altogether.

Problem #2: Wind Slab

Problem Type
Wind Slab
Aspect/Elevation
NNEESESSWWNW
Likelihood
CertainVery LikelyLikelyPossibleUnlikely
Size
Historic (D4-5)Very Large (D3)Large (D2)Small (D1)
(4/14/2026)

Visual clues of wind transported snow and potentially wind loaded slopes. 

Photo: Dallas Glass

It's been a few days since the most recent wind loading event, but that doesn't necessarily mean unstable slabs are gone entirely. More likely, they are trending harder to find and trigger. Unstable slabs are most likely to persist at higher elevations (such as volcanoes) on shady slopes harboring cold snow. Keep these slabs in mind as you climb in elevation. Use cornices, wind lips, and textured snow surfaces to point you in the direction of wind-loaded slopes. If the snow underfoot feels hollow and extra dense on top, you might be standing on a hard wind slab.

Look for these slabs near ridgelines, under cliff bands, or on steep rollovers. These will be hard to test for, so you're better off sticking to the softer snow on less wind-affected slopes. 

Forecast Discussion

The last avalanche forecast for the 25-26 season will be for Sunday, April 19th. Mountain weather forecasts will be published each afternoon through May 3rd. A huge thanks to everyone in our community for your support this winter!

Friday was generally warm and sunny in the West South. Patchy clouds moved through but did little to alleviate the sunlight, and temperatures climbed 5–10°F warmer than Thursday. Observations from Mount Saint Helens at 7,100 feet noted a newly formed surface crust and 2.5' fresh snow underneath. A few recent wet loose avalanches were spotted around the Worm Flows climbing route. 

The most recent storm brought feet of new snow, with the highest totals on the volcanoes. That snow was capped with a surface crust on Friday morning that broke down with daytime heating. Expect similar conditions Saturday, with less overnight cooling and a higher daytime temperature spike. Increased cloud cover will be the most notable difference compared to Friday.

As it gets later into the spring, operations are shutting down, and trailheads are getting quieter. This time of year, the weather can change quickly in a single day and even vary between drainages. Combined with fewer observations available, uncertainty is higher. If you’re headed out Saturday, take a thoughtful approach to snow stability, pay attention to the weather and surface snow, and give yourself options if conditions worsen.

This information is provided by the U.S.D.A. Forest Service and describes general backcountry avalanche hazard and conditions. It does not apply to ski areas and highways where avalanche mitigation is conducted.