Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Thursday will be another day with light snow and rain with moderate winds. Triggering avalanches in wind-drifted snow is possible, so use clues like stiff textured surfaces or deep pillow-like drifts to identify where these slabs exist. Choose low-angle terrain or scoured ridgelines and slopes for travel where you find wind-drifted snow. 

Avalanche problems

  • Wind Slabs

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

    At mid and upper elevations, moderate winds and a few inches of new snow may form shallow fresh wind slabs where you could trigger an avalanche. Expect more snow and larger avalanches further west, towards the Cascade Crest, particularly in the HWY 410 corridor close to Chinook Pass. Slopes below ridgelines and the base of cliffs are likely spots for wind slabs to form. Look for textured surfaces or stiff, hollow-sounding snow to identify wind slab locations. You can also use quick hand pits, your probe, or poles to feel for stiffer snow over softer snow. If you see shooting cracks in wind-stiffened snow, this is a sign to choose low-angle terrain. At mid-elevations, wet loose avalanches may become increasingly likely in the late afternoon, and the rain/snow line creeps up to elevations with more recent snow. We expect most of these avalanches to be small but use caution in high-consequence terrain where a fall could have unfortunate outcomes. Cornice falls are common this time of year and are a hazard on their own, but they can also trigger slab avalanches on the slopes below. Don't linger for long beneath these monsters. 

    (2/28/2023)

    Look for pillow-like slabs and wind-textured snow to help you identify slopes of concern. 

    Photo: Katie Warren

Avalanche Discussion

Areas closer to the Cascade Crest near White Pass picked up 3-5" of snow on Wednesday, while Chinook Pass had up to 12"! Thursday's storm will bring another few inches of snow and moderate winds. With the recent clear nights and warm days, there may be slick or weak snow surfaces. So check the bond with the old snow surface as you travel. If you find the new snow slides easily, avalanches are more likely.

This isn't a particularly cold storm, and freezing levels will increase throughout the day. So, you may find some wet snow avalanches at low and mid elevations as the day warms up. The diurnal warming and dynamic spring weather can lead to rapidly changing avalanche conditions. New snow concerns like wind and storm slabs can quickly become wet snow problems in the afternoon. Make frequent observations, and be prepared for changing conditions and snow stability. 

On Wednesday, an NWAC forecaster in the Ahtanum area found around 6" of new snow above 6000ft. New snow depths at lower elevations were significantly less, with rain down at the Snopark. A profile at approximately 6600ft on a NE aspect showed a stout crust below the recent snow. Shovel tilt tests produced moderate results with clean shears on this crust. In sheltered areas, there isn't much of a slab over this crust, but it could make wind slab avalanches easier to trigger. They also found the facets over the Early February Crust to be moist and rounded. This persistent weak layer is getting stronger and, combined with the stout surface crust, makes avalanches on this layer unlikely. However, there is always lingering uncertainty with these tricky, persistent weak layers, so step into large, north-facing alpine terrain with this in mind. A big warm-up or powerful storm could also bring this problem back to life. 

Observations have been sparse. Help create a more accurate forecast by submitting your public observations here. 

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