Avalanche forecast

West Slopes Central

Northwest Avalanche Center
View on map

Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 6 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Loose dry avalanches will be the primary concern on Friday. But low-density surface snow is everywhere and available for wind transport. If winds increase, that same snow could quickly be redistributed into shallow wind slabs in exposed terrain. Monitor surface conditions and watch for signs of increasing wind throughout the day.

Avalanche problems

  • Loose Dry

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

    Small loose dry avalanches are possible on slopes steeper than about 40 degrees. While generally small, they can entrain enough snow to carry you downhill, especially in sustained fall-line terrain. Consequences increase above gullies, cliffs, or other terrain traps. Pay attention to how much snow is moving downhill with you. Have a plan to pull over and let it run its course if it gets to be too much.

    (4/17/2022)

    Shallow natural dry loose avalanches initiated off cliffs and trees by filtered sunshine.

    Photo: Christopher Van Tilburg

  • Wind Slabs

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

    Light surface snow is easily transported. Even moderate winds could quickly form shallow slabs near ridgelines, convex rollovers, and cross-loaded gullies. Watch for drifting snow, rounded pillows, hollow-sounding slabs, or cracking underfoot. Test small features before committing to larger slopes and avoid steep terrain that shows recent signs of wind loading.

    Fresh, reactive wind slabs were found in Cascade Pass in the West North forecast zone on Thursday, so some areas have already seen wind transport and have slabs in place.

    (11/21/2023)

    An example of strong wind drifting snow off a ridgeline. Fresh, reactive slabs could be forming on the slope below.

     

Avalanche Discussion

The balance between sun and temperature should limit wet avalanche activity on Friday, but don’t rule it out entirely. Pay attention to sunny slopes overhead and watch for wet avalanche indicators like rollerballs or pinwheels if the sun comes out and temperatures rise.

It's hard to get an exact read on the new snow amounts of the past 36 hours. SNOTEL weather station data can be extra fickle during periods of cold temperatures and light-density new snow. That being said, there is a foot or more of new snow in some areas at mid and upper elevations, and expect 6 inches just about everywhere, even low elevations.

While the light snow, cold temperatures, and powder conditions have provided a welcome break from the warm and wet that has characterized this winter, they bring their own concerns. Patches of faceted snow and surface hoar have been identified at several recent interfaces. Also, light-density snow as we have now facets more readily than the dense snow typical of this region, and cold temperatures slow strengthening. While we still don't have well-developed weak layers like those found in other parts of the Cascades. The take-home point is that there's currently enough weak snow out there to not take our typical wet, dense snowfall for granted when it returns.

Regions covered