Avalanche forecast

West Slopes North

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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Stay alert to changing conditions as concern for wet loose avalanches will increase throughout the day. Steer around steep sun-exposed slopes by the afternoon and continue to watch for unstable areas of wind drifted snow high in the alpine. 

Avalanche problems

  • Loose Wet

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

    Loose wet avalanche activity has been ongoing during the past week during periods of sunny skies and warming afternoon temperatures. This pattern will continue Friday. The sun will need to battle some clouds and break down a melt-freeze crust on solar aspects. By the time this happens, snow surfaces should be wet, weak, and primed for loose wet avalanches. Monitor changing conditions throughout the day, and keep your return routes in mind. The loose wet hazard will be limited early morning and where you find firm and frozen snow surfaces. The best chance for loose wet avalanches will be during the afternoon, especially on upper elevation south and west aspects. Watch for snow shedding from trees and rocks, and rollerballs and pinwheels following soon after. Although most loose wet avalanches are expected to be small, some could grow large and run far downslope. Steer around steep terrain with evidence of wet snow and move to shaded or lower angled slopes to avoid the problem.  

    Example photo of loose wet avalanches crossing common travel routes on the south side of Table Mountain

  • Wind Slabs

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

    You are most likely to trigger a lingering wind slab in the alpine on northerly convex slopes steeper than 35 degrees and in areas below cornices or rock bands. Several human-triggered wind slabs and a few close calls occurred earlier in the week. Fortunately, there were no full burials or injuries. Much of the recent avalanche activity occurred above treeline. Avalanches in wind drifted snow could break 6in-3ft deep. Continue to approach upper elevation terrain cautiously, and give cornices a wide berth. These unpredictable features are large and overbuilt and can break further back than you may expect or fall onto slopes below acting as huge triggers. Seek out terrain less than 35 degrees where you find recent avalanches, cracking, collapsing, or evidence of wind drifted snow. 

    (3/8/2021) A snowboarder-triggered avalanche on Shuksan Arm that broke 1-3ft deep, 200ft wide, and ran 300 vertical feet. The snowboarder dropped the cliff above the slope and triggered the avalanche upon landing. They were caught and carried but remained on the surface with no injuries. Photo: Pete Durr

Avalanche Discussion

Natural wet loose activity occurred during periods of sunshine March 8-11, especially during the afternoon hours. From March 4-7, over 2ft of new snow accumulated above 4000ft throughout the West North Zone. Deposits of wind-blown snow are several days old, but several human-triggered wind slabs were reported March 6-8. Triggered wind slabs occurred in upper elevation terrain on Shuksan Arm, Table Mountain, and on the south side of Mt. Baker. An impressive icefall avalanche also occurred on Mt. Shuksan's Hanging Glacier on Tuesday (photo below). Be heads up with these transitional spring conditions as icefall and cornice fall may continue. Minimize exposure to these and other overhead hazards especially if you venture into the alpine. 

Deep persistent slab avalanches are dormant and unlikely, but the snowpack structure can still be found throughout the region. The Mid-January PWL is now 10ft below the snow surface and continues to gain strength. The last deep slab avalanches in or near the West North Zone occurred several weeks ago. Major warming events later in spring and summer could trigger further rounds of avalanches on this layer. Keep in mind the consequences of these massive avalanches and give yourself an extra margin of terrain in large avalanche paths.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regions covered