Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Avalanche danger will increase as a storm continues to deposit snow and blow throughout the day. It's likely that you could trigger avalanches in new storm snow deposits deeper than about 6 inches, although in thicker wind-drifted areas it'll be easier to trigger larger slabs. Today's a day to steer around steep slopes that have sufficient new snow deposits, especially if you're identifying instabilities like recent avalanches or long shooting cracks running from your feet or sled. 

Avalanche problems

  • Storm Slabs

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

    Expect avalanche danger to edge towards the upper end of Considerable as the day progresses. On non wind-affected slopes, storm slabs are likely to avalanche with a human trigger. During the first half of the storm, temperatures are forecasted to increase, meaning we could see a bit of an "upside down" snowpack, leading to more touchy avalanche conditions. Thankfully temperatures will cool as the storm progresses, but don't expect the danger to decrease so quickly. Wind will ramp up and redistribute storm snow in exposed areas into wind slabs, which is where you will probably encounter the largest and most reactive slabs. Expect to find more of this as you gain elevation. During this storm, it's best to play it safe and identify any locations where more than about 6 inches of storm snow exists, and avoid these areas on slopes steeper than 35 degrees. 

    If we experience periods of intense snowfall, shallow natural avalanches could occur during this time, as the snow struggles to adjust to the rapid change. Natural avalanches are possible with Considerable avalanche danger. Most avalanches will likely fail within the new storm snow, which will grow in size throughout the day. This means you could trigger an avalanche around 6 inches to a foot deep, or possibly deeper as the day continues. However, there are a number of crusts, storm interfaces, and a graupel layer in the top couple feet where there's a small chance a failure could occur on one of those deeper layers. In general, a large variety of surfaces exist beneath the new storm snow layer we'll be getting. 

    Pay attention to red flags as your strongest indicators to avoid steep slopes. This includes recent avalanches, long shooting cracks, and whumphs. Other red flags include heavy snowfall and strong wind, both of which you'll probably see on Thursday as well. When in doubt, stick to lower-angle slopes as the storm passes through. 

    Fresh storm slab avalanche crowns on Shuksan Arm near treeline which happened earlier this month. This is similar to what you might see on Thursday.

    Photo: Mt Baker Patrol

Avalanche Discussion

Several small natural and human-triggered avalanches were reported during the much-higher-than-forecasted snowfall amounts we received on Tuesday. One human-triggered avalanche failed almost 2 feet deep on a south-facing crust. It's not out of the question this may happen again during the storm. On Wednesday the snowpack settled a bit and avalanche activity slowed. We're now expecting around a half inch of water, or 6 inches of snow Wednesday night, and a bit more than that amount during the day, with winds increasing to strong around midday with the frontal passage. 

Keep in mind that if you're in steep avalanche terrain and there's any chance you'll trigger an avalanche, make sure you've got a clean runout and an exit strategy in case you do trigger an avalanche. Even a small slide could be deadly or cause serious harm if you're on a slope with terrain traps.

Snow and avalanche conditions in the zone vary extensively.  This is a day similar to others, where there's a lot of variability within the zone and from slope to slope. What you see in one location might vary quite a bit from other areas. Use this forecast as a starting point to further evaluate slopes during your day's outing. If you travel anywhere in this zone, whether you see any avalanches or not, please send in an OBSERVATION so that we know more about the conditions in the area. 

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