Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Very large and dangerous natural avalanches that could kill you are expected on Wednesday. Avoid all avalanche terrain, which means steep slopes and lower-angle terrain beneath steep slopes. This includes travel on roads and trails at lower elevations where sneaky gullies  cross the road, and they originate high above on steep mountain slopes. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Rising temperatures, strong winds, and almost 3 feet of snow by the end of the day Wednesday are forecasted. This is a great recipe for natural avalanches, which may reach very large in size, as we will probably end up totaling 4 to 6+ feet of snow since the 24th. It's not out of the question that all this recent snow may slide. There's even a very small chance that snow could slide a foot or two deeper than these recent layers, all the way down to the Early February Crust, where in some places we've been finding weak snow above the crust. Avoid traveling in all avalanche terrain, including flat or lower-angle terrain beneath large steep slopes, which you might not even be able to see up above you. It will likely be unsurvivable if you trigger or get caught in an avalanche. 

    Last year in the neighboring West North zone, some unsuspecting folks drove up Church Mtn Rd off Hwy 542 right after a huge snowstorm. There was no snow where they drove. In the couple hours they were up there, a very large natural avalanche came down a subtle gully and their vehicle was trapped behind a debris pile well over 10 feet deep. It was stuck there for at least a month. Wednesday could be a day like this, so don't get lulled into complacency by traveling in a lower elevation area where there is very little snow, thinking that it means you're alright. Beware of traveling across subtle gullies and abrupt swaths of smaller trees next to large trees (that might indicate an avalanche sweeps through the area) at lower elevations if there are steep mountains nearby. 

    (2/27/2024)

    A very large natural avalanche in the neighboring West North zone on a northwest aspect at 5800' withe the partly filled-in crown outlined in red.  Likely released during the storm on Feb 25th. (HS-N-D2.5-U)

  • Loose Wet

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

    Snowlines are rising through the day on Wednesday. There's 1-2 feet of fresh snow at the upper parts of the lower elevation band, and snowline is forecasted to rise to about 4000ft. Previously cold dry snow will get heavy, wet snow on it, and some rain as well, so wet loose avalanche could result.

    Avalanches will start shallow, running in the top few inches of the snow. As more rain falls, avalanches could grow deeper, with the chance of a wet slide wiping out all the snow above the Early February Crust. This may only be about 6 inches deep at 3000ft if there is a smooth surface for the snow to run on, but when we're getting above 4000ft, there might be closer to 2 feet of wet snow running down a slope, enough to cause serious harm if you're caught.  This is one more reason to avoid travel on or below steep slopes on Wednesday. 

    (2/21/2024)

    A natural wet loose avalanche initiating from steep, rocky terrain, which is where you might see avalanches starting from on Wednesday. 

    Photo: Zack McGill - Cascade Mountain Ascents

Avalanche Discussion

Avalanche activity will likely increase throughout the day as more snow falls, and it gets heavier and more wind-affected. We expect natural avalanches to start overnight and continue throughout the day. Some avalanches may only occur in the newest snow layer, which might still be 1-3 feet deep. But avalanches may fail 6 or more feet, taking all of February's snowpack with it. Visibility will likely be poor, and you won't be able to see either overhead hazards like avalanches coming down or even hazards like cornices or wind lips right in front of you, that you might fall off of. 

Observers in the last few days reported a whole variety of conditions. In some non wind-affected areas backcountry travelers only encountered dry loose avalanches. However, neighboring zones have seen a few large and very large avalanches naturally failing in the last few days, which likely happened in the West Central zone as well. The avalanches may have failed as deep as the Early February Crust. We believe avalanches failing down to this layer will probably be few and far between, but we're not quite sure. A number of other weak interfaces exist above the Early February Crust, which are all layers we may see avalanches on during Wednesday's storm. 

Travel will be very challenging as snow gets heavier and deeper. Snow immersion syndrome is a very real hazard for Wednesday. You could be trapped around trees, but there are also many subtly hidden creek holes and other holes that have been recently covered that you could get trapped in as well. Winds will be ripping around on mountaintops, valleys, and everywhere in between. Expect an adventurous day in the mountains with heavy snow, rain, and wind on Wednesday. 

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