Avalanche forecast

West Slopes South

Northwest Avalanche Center
View on map

Avalanche danger

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Out of date — this forecast expired 4 years ago.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

Highlights

Stormy weather will result in dangerous avalanche conditions around the zone on Tuesday. Recent avalanches should grab your attention as we continue to load the snowpack You’re more likely to trigger a slide on slopes over 35 degrees, especially if they’re wind-loaded or convex.

Avalanche problems

  • Storm Slabs

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

    Anticipate Storm Slabs to develop at all elevations on Tuesday as a potent storm nips the West South zone. Avalanches will be easier to trigger on slopes over 35 degrees, especially if they’re wind-loaded or convex. All of the snow above the 2/3 interface should be in play for avalanches during the day. As is often the case in the Cascades, the winds will also be a player during this storm. So be on the lookout for wind-loaded slopes where slabs may be thicker and possibly more reactive. They’ll be more likely on the leeward side of ridgelines or on convex slopes. 

    You should take the time to dig in the snow with your hand or shovel to check for potential points of failure and see if there is heavy snow over lighter snow (upside-down). Using small test slopes or uptrack tests during your travels can give you an indication if these failure points are being triggered by your weight. If you notice that blocks are failing easily during your tests, suspect a slope to be wind-loaded, or see red flag signs of avalanches such as shooting cracks, you should avoid slopes over 35 degrees. 

    (2/5/2023)

    Natural slab and loose avalanches on Edith's Knob near Paradise on 2/5. [SE 5800ft]

    Photo: Dallas Glass

Avalanche Discussion

The biggest storm we’ve seen in about a month is headed for the West South on Tuesday. We should roughly double the amount of water we have received since Friday in a 24-hour period and in some locations eclipse it. Paradise should far exceed the rest of the zone in terms of water numbers and if you happen to find yourself near Mount Rainier, know that you will be dealing with High avalanche danger and travel in avalanche terrain is not recommended. 

We will be focusing on the snow above the 2/3 interface for this storm, which is currently 1-1.5 feet below the surface in most areas of the zone. At this interface, you could find firm crusts or weak near-surface facets depending on exposure to wind or sunshine. Observations from the weekend indicate that shallow slabs were failing at or above this interface in locations such as Paradise, Tatoosh, Crystal Mountain, and White Pass. On Monday, skiers triggered a slab avalanche near Crystal Mountain and one person was caught and carried. Avalanche professionals near White Pass reported small column tests failing at the 2/3 interface.

These recent avalanches, albeit many of them shallow, are red flag signs that the snowpack needs more time to heal. Instead of getting that time, it is about to get even more of a load, and likely will continue to be unhappy. The added depth of Tuesday’s snow means these avalanches should be larger and possibly more consequential than those seen in recent days.

At lower elevations, we could see some rain or a rain/snow mix. This has been the case most of the weekend and these elevations should be well-suited to handle any incoming liquid precipitation. That said, as you ascend toward the upper reaches of the below treeline band, you could see some avalanches on steep features over 35 degrees. These slides could be either wet or dry depending on the moisture content of the new snow at this elevation. 

We do have some deeper layers of interest between the 2/3 interface and the MLK crust. While we don’t anticipate any of them coming into play tomorrow, some of them could via stepdown by the right avalanche in the right terrain.

Regions covered