Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Snowfall is expected to continue throughout the day, and temperatures will slowly rise. Choose lower-angle slopes and terrain that will not present additional hazards due to a thinner, early-season snowpack. As you gain elevation, more wind and snow will increase the avalanche danger. 

Avalanche problems

  • Loose Wet

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

    A subtle uptick in the snowline throughout the day on Sunday could result in small wet loose avalanches. They may be triggered by tree bombs above steep slopes, or you could initiate one. A wet loose avalanche may happen in areas where the snow isn't very deep, or even without a continuous snow layer. In some cases, especially at the lower elevations, triggering or getting caught in an avalanche probably won't be a problem unless you're in a high-consequence area where a small slide could bury you deep in a gully or push you off a cliff. If you notice snow getting wet and sticky, or see small rolleballs running down steep slopes, be aware that wet loose avalanches could result. 

    Example photo: rollerballs could be indicators that wet loose avalanches may occur. 

  • Storm Slabs

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

    Depending on your elevation and where you are in the zone, we may receive about 6 inches of snow during the day.  Temperatures will slowly increase during the day, with a few inches of snow falling in the lower-elevation band Saturday night. Snow levels will rise up into the mid-elevation band, and snow surfaces will get heavier throughout the day.

    You can find instability where a stronger slab, or heavier snow, sits over a slightly softer layer of snow. This could be the case as temperatures increase, or in areas where wind drifts snow into heavier slabs. Search out strong over weak snow layering by using simple tests like hand pits and small test slopes. Avalanches could be limited to the new snow layer or to additional recent snowfall.  Long, shooting cracks and new avalanches are obvious red flags that avalanches can happen.  Stick to lower angle terrain as this storm continues, especially if you find any red flags during your outing.  

    Example photo: Slopes that could still have shrubs poking through may still have enough of a continuous slab to avalanche. 

Avalanche Discussion

Sunday's weather is not as remarkable as the next few days, when we can expect several inches of water, resulting in feet of snow at upper elevations. While challenging travel may be the name of the game over the next few days, the flood warnings at the lower elevations will give way to increased avalanche activity on snow-covered slopes. 

Lower elevations have very little snow, but the snowpack is growing at higher elevations. Last week I walked up Evergreen Mountain. It was easy to walk, without requiring any flotation up to the summit at 5500ft. We've received more snow since then, and as you go higher, conditions will change quickly. The Lyman Lake weather station near glacier peak and on the divide, almost at 6000ft, is reporting over 4000ft of snow. Midway down the snowpack at upper elevations, a mid-november crust exists. Below about 5500ft, the crust might constitute the bottom portion of the snowpack. 

Most slopes do not present as they might in mid-winter. Snow has not yet smoothed the landscape, and features are very different from how they may look in a month or two. This could mean that your travel behavior should be different- gullies exist where they may not mid-winter, and some slopes may be steeper than when they're filled in with snow. Scree surfaces may not yet be covered, making for a minefield of hazards. 

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