Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

It will be a bitterly cold and windy day on Thursday, so you might not want to press your luck too much in the backcountry. Wind-loaded slopes are where it's most feasible to trigger an avalanche large enough to bury you. Consider navigating around slopes steeper than 30 degrees where you find pillow-like drifts and cornice development, particularly on aspects and elevations that harbor a weaker snowpack. 

Avalanche problems

  • Wind Slabs

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

    An easterly wind event started on Tuesday and not only continues but strengthens into Thursday. With low density snow available for transport throughout the week, you could trigger old and new slabs on lee slopes. Wind coming from the east has a tendency to load surprising slopes and catch backcountry travelers off guard. Older slabs will be stiffer and harder to trigger but larger and more consequential. It's more plausible to trigger a fresher, smaller slab that could knock you off your feet and carry you over hazards such as rocks and cliffs.

    Wind-loaded snow is often found just below ridgelines and in cross-loaded gullies. Red flags are cracks shooting out from your skis or sled and recent slab avalanches in similar terrain. Visual clues such as cornice development, rippled snow surfaces, and blowing snow that will be visible throughout the day will help direct you to the side of a ridgeline where wind-loaded snow may be lurking. 

    Although fairly unlikely, a triggered wind slab could "step down" and become a more treacherous persistent slab avalanche on newly wind-loaded slopes. Read below for more details.

    (2/10/2025)

    I found some cracking in wind loaded slopes near Mission Ridge on 02/10.

    Photo: Payton Schiff

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1.5–2

    The likelihood of triggering a potentially fatal avalanche is low but not impossible. This zone hasn't had much activity or signs of instability on weak snow layers associated with the January Drought Layer (JDL) in several days; however, the distribution is nearly impossible to pin down. What we do know is that poor snowpack structure exists in many areas, and easterly wind may have made lee terrain more perilous. 

    This particular persistent slab problem has been even more tricky to manage than your average uncertain persistent slab problem. You may or may not see clear signs of instability - cracking, collapsing, or recent slab avalanches - telling you to back off before it's too late. Use the clues laid out in the wind slab problem to help you identify wind-loaded slopes, understanding that a small wind slab avalanche can "step down" and trigger a deadlier persistent slab avalanche. You can reduce your risk by choosing slopes that are shorter, more planar, and free of hazardous cliffs or terrain traps. When in doubt, default to lower angle, sheltered terrain.

    (2/1/2025)

    This intentionally triggered persistent slab, propagated the entire width of the feature. It failed on facets over a thin crust. ENE, 6200ft, SS-ASc-D2-R3-O, 20-24 in deep, 200 ft wide.

    Photo: Dallas Glass

Avalanche Discussion

Cold weather has been a hot topic this week. Weather stations at middle and upper elevations have recorded temperatures as low as -1°F and around 3°F at lower elevations. Thursday is not only no exception but an even more biting day to be outside with increased wind speeds and cloud coverage. A 5°F day coupled with 30mph wind creates a wind chill value of -19°F. A backcountry emergency will quickly go from bad to worse with this kind of weather, so be prepared with extra layers, reliable communication devices, and maybe a thermos or two of hot cocoa. 

The likelihood of triggering a large persistent slab avalanche is decreasing, but the unique nature of this particular persistent slab problem has many long time avalanche professionals still traveling conservatively. An NWAC forecaster in the Mission Ridge area on Monday found poor snowpack structure but unremarkable snowpack test results. In the nearby Stevens Pass zone, observers reported cracking and propagating snowpack test results. This problem has been hard to pin down due to the high variability of snowpack surfaces leading up to new snowfall at the end of January. Additionally, sustained cold weather has slowed down the healing process for the JDL. Stack the odds in your favor by choosing well-supported terrain and enjoying high-quality powder riding in more sheltered terrain.

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