Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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In sintesi

Expect a dangerous day in the mountains with large, human-triggered avalanches very likely as a storm deposits snow Friday night through Saturday. Avoid steep slopes, and consider steering around lower angle or flat areas beneath large avalanche paths, as natural avalanches are likely.  Avalanches could occur on any steep slopes where enough snow lands, however, they will be more reactive and larger in wind-loaded areas. 

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1.5–2.5

    Expect to be in the company of large avalanches if you travel near avalanche terrain on Saturday. If you are involved with an avalanche, it will probably be large enough to bury and kill you. Snow will rapidly load throughout the night and into the daylight hours, possibly totaling 2 feet or more. Strong winds are forecasted at night, tapering to moderate during the day. 

    Any location where you find deep deposits of recently-fallen snow is suspect, as it probably hasn't had time to adjust. However, wind-loaded slopes are more likely to avalanche, and they will probably produce larger avalanches. Layering may be complex with this storm, as heavier slabs could develop with the wind overnight, and a smoother lower density coating of snow could bury it later on, making the thicker slab less obvious. 

    To set yourself up for success, steer around slopes greater than 30 degrees holding new snow on Saturday. Not many times yet this year have we suspected many natural avalanches to occur, but right now is one of those times. This means that rather than just avoiding steeper locations, avoid traveling beneath large, steep slopes as well. 

     

     

     

    (3/15/2022)

    An example of a large storm slab avalanche which occurred last year in the Baker backcountry, running approximately 3 feet deep. This is similar to what you might see (if visibility allows) on Saturday.

    Photo: Adam Ü

Avalanche Discussion

There is a possibility that avalanches could fail deeper than the new snow layer of 1 to 2+ feet. Last Sunday a rider was surprised in the Baker backcountry by triggering an avalanche on a steep, wind-loaded slope. You can read the report HERE. The crown was up to 4 feet deep and the rider was lucky enough to emerge unscathed. Most of the nearby slopes had tracks on them, yet there were no other avalanches of that nature. Weak, faceted grains were found near a crust, where it failed. This layer is getting buried deeper and we know very little about it, but a large load of snow and/or a human trigger could awaken it. We've had several smaller storms and wind events in the last several days as well, so there's a chance an avalanche could break at one of these interfaces, becoming larger than what you might otherwise expect.

This storm is an unusual southerly weather event, so snowfall totals could vary greatly depending on where you are in the zone. The Baker backcountry and south side of Baker are expected to get more snow than other locations, so you may find avalanche conditions differing depending upon your location.  No matter where you are, you can expect to see bullseye clues, or red flags, on Saturday.  There's near certainty that recent new snow and wind are present. If you see an avalanche, that's a bonus point, in addition to being the most obvious indicator to avoid nearby slopes. Another red flag you might come across is collapsing or cracking in the snowpack.  These indicators are all suggestions to wait until enough time has passed -at least a day- for the new snow to settle out before making your way onto steeper slopes. So far this winter we've seen a lot of mellower days, but that's not today. Stay on alert if you're heading into the backcountry. Pay attention to the terrain you're traveling through. This isn't the time to try and thread the needle with the rapid loading of new snow. Sticking to lower-angle terrain and steering around runouts is a good plan for making it through the day. 

 

 

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