Avalanche forecast

West Slopes South

Northwest Avalanche Center
View on map

Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Up to a foot of snow could fall from Monday through to the end of the day Tuesday in some areas of the zone, mainly the volcanoes. New snow and moderate winds could redistribute the snow into thicker drifts, leading to dangerous conditions. Search for wind loaded features, and avoid them on slopes steeper than 35 degrees. 

Avalanche problems

  • Wind Slabs

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

    Expect to find freshly built winds slabs throughout the West South Zone on Tuesday. Search for drifted pockets of snow developing on the leeward side of ridgelines, convex features, or in rocky terrain such as at the base of cliffs and in confined chutes. These slabs could be larger and possibly more reactive as you ascend in elevation or in areas that receive more significant snow totals. Regardless of your location, you may encounter some unusual loading patterns with slabs forming on aspects you’re not used to or more cross-loading than usual. Identify actively blowing snow and textured snow surfaces to help you determine where wind-loaded features are. As it is likely that you could trigger an avalanche in these freshly drifted deposits, avoid them on slopes greater than 35 degrees on Tuesday. Do not ignore clues such as recent avalanches, whumphing, or cracking from your steps, as these are obvious indicators of weak snow and sure signs that you could trigger an avalanche on a nearby steep slope. 

    (4/18/2022)

    Small slabs cracked in wind drifted locations at White Pass on Monday. This is on a west-facing slope at 5800'. With more snow and wind overnight into Tuesday, expect to see more of this Tuesday.  

    Photo: Dallas Glass

Avalanche Discussion

Some areas in the Cascades had extensive warming with sunlight on Sunday and a subsequent stout crust formed. Monday at White Pass observers noted only a subtle crust from Sundays warming on south-facing slopes, which was noticeable on skis but didn't hamper turns. Temperatures have since remained relatively mild but Monday night we're expecting to see a few to several inches of snow throughout the zone, and cooling temperatures. In some areas, the new snow may cling to the crust, but in more exposed areas the new snow could blow away in the wind. The crust is challenging to travel over, as the smooth surface could be slippery. Steeper crusty surfaces may be textured with rollerballs and wet loose avalanche debris- not the most pleasant surface to move over. 

The surface the new snow sits over could help drive the size and likelihood of you triggering a slide. Take a moment to check the bonding of the storm snow to the old surface before committing to a slope. A crust could make an excellent sliding surface for any wind drifted pockets that deposit on the crust.  We anticipate most avalanches to be isolated to the new accumulation, but on those shadier slopes we could see some avalanches break into older layers. There is currently 2-3 feet of snow sitting above the 4/8 interface which is the maximum depth, however unlikely, that we expect any avalanches could step down to currently. 

We have extended our forecasting due to the stormy weather to help you out. That means we still need you to share information with us by submitting public observations about what you're seeing out there. Help us build a better product for you.

Regions covered