Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

Avalanche danger may be on Moderate up high, which looks a lot like the day before, and the day before that, but it doesn't mean you're in the clear. Reports keep coming in throughout nearly all of the Cascades of human-triggered wind slab avalanches that have predominantly occurred at upper elevations. Avoid steep, wind-loaded slopes, which mainly exist at upper elevations, to avoid getting caught in an avalanche. 

Avalanche problems

  • Wind Slabs

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

    Reports of human-triggered avalanches came in from nearly everywhere in the Cascades over the weekend. Triggering an avalanche might be a bit more stubborn, as it's been a few days since many formed, but we still expect it's possible to trigger an avalanche in new or old wind slabs. These will predominantly exist and react to a human trigger at upper elevations. Nearly all the triggered avalanches were in upper elevation, wind-loaded terrain. 

    Lower the odds of getting caught in an avalanche by avoiding wind slabs on slopes steeper than 35°. All the signs might not be obvious- you might not see red flags like shooting cracks. The slabs might be hidden and subtle.  You'll probably be able to identify a slightly stiffer feel beneath you, however. You might be able to get away with travel on one slope, but not the one next to it. This isn't the time to push your luck. 

    Wind is continuing on Tuesday, and we might pick up an inch of snow. If more snow falls than forecasted, danger could be higher. The wind direction is shifting subtly, to SW. This means that there may be low-density snow that this wind from a different direction could transport into freshly formed slabs, that are possibly more reactive. Many of the older slabs are probably becoming more stubborn, and it's true, most of the reported avalanches are a few days old. But conditions haven't changed too much since then, and we still believe it's possible you could trigger an avalanche on those higher elevation wind-loaded slopes. 

     

    (2/19/2024) This avalanche was triggered in the West South zone on Monday. They've gotten way more snow than us, but it's still scary seeing what's getting produced somewhere not too far away from the West Central zone on Monday. 

Avalanche Discussion

I went to the north side of the Mountain Loop Highway on Monday and made it up to 5300ft. At that elevation, the snowpack was just over 5 feet, and a little over a foot of newer snow was evenly distributed over the Early February Crust (EFC). There's been a lot of recent wind, and in the last few days (especially Friday) I saw extensive flagging in the Hwy 2 corridor from 4,000ft-5500ft. Surprisingly, I didn't find any evidence on the slopes I traveled, although where I was may have been sheltered by nearby mountains. Even at this elevation, snow on all aspects was heavy, and unless winds are very strong I wouldn't suspect much transport to occur even if it were windy. I didn't see transport on any nearby peaks either. 

I found small weaknesses midway in the snowpack above the EFC (see pit photo). Where I traveled, I wasn't concerned with failures at that weakness. However, at higher elevations and with wind loading on top, an avalanche might occur on that layer. Throughout the Cascades, we've been finding this layer a little ways above the EFC. We've also been finding weak snow above the EFC. In some locations, the snow just above the EFC is well-bonded (like my observation from Thursday), and in other areas, it hasn't been. Right now, except in wind-loaded areas, it's probably just over a foot below the surface, and may not have enough of a slab to fail. However, with a wind slab on top, failures might break down to this layer. 

Thin snow cover, bare patches, and crusts exist at lower and mid elevations. Many unexpected holes are present in these areas as well.  Snow at the lower and mid elevations might get moist or sticky on Tuesday, but probably not enough that you'll see avalanche activity.  If you make it into the backcountry, send us an observation so you can help contribute to better forecasts in the zone!

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