Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Very dangerous avalanche conditions will exist on Monday as freezing levels progress upwards and rain continues to fall. The largest and most reactive avalanches will be at higher elevations, where the snow is deeper and was dry not long ago - avoid where avalanches start, run and stop up here. Meanwhile, lower elevations probably won't have too much new natural avalanche activity, but don't linger beneath large avalanche paths connected to upper elevations. 

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1.5–2.5

    We expect peak avalanche activity to have happened overnight, as snowlines are expected to creep all the way to the top of the upper elevation band. Large wet avalanches could remain very likely as temperatures increase throughout the day. The most activity and largest slides will be in the upper elevation band, where there more previously cold, dry snow existed.

    Avoid all steep slopes on Monday since they're quite soggy and could avalanche with a trigger. If you make your way to the upper elevation band, also steer around areas where avalanches run and stop. Beware of these large, scary overhead hazards. 

    At lower elevations, warm temperatures and rain already impacted these slopes since Saturday night. The snowpack has probably adjusted, and not many natural avalanches are expected to fail here. However, it may not be a bad idea to avoid lingering beneath large avalanche paths, such as gullies, that connect to upper elevations.

    Large and destructive wet avalanches are very likely at upper elevations. Some may travel down to lower elevations. 

  • Glide Cracks

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2

    Snow shifted to rain at mid elevations midday Sunday. By Monday, some usual glide locations where steep rock slabs exist may begin to move. If you see large, gaping cracks, it'd probably be best to give them a wide berth, as they might avalanche unexpectedly. 

    We've received a lot of snow and wind lately, and a few cornices have failed recently. It wouldn't be surprising if a cornice chunk fell, possibly triggering an avalanche on the slope beneath it. Alternatively, soggy chunks of snow perched on rocks may also unexpectedly fall. 

    Lastly, the Jan 3 layer is our most notable crust beneath the surface. It's probably about 3 feet down, but highly variable due to elevation and wind-affected surfaces. If we get enough rain percolating down to this layer, there's a small chance the surface of the crust could lubricate and we could see resulting highly unpredictable wet slab avalanches on this layer. We don't expect this to happen, but it's not completely out of the question. 

    Example photo: If you see glide cracks, this is a good day to avoid traveling beneath them. 

Avalanche Discussion

Avalanche Fatality: On Friday, January 9th, four backcountry skiers were caught and carried by a large avalanche while descending near Longs Pass in the Teanaway River drainage. The slide occurred on a S to SE facing slope at approximately 6200ft. One member of the party was not buried. Another teammate was partially buried but injured. The other two individuals were fully buried. During the initial rescue, the team located one of the buried victims, who did not survive. Despite the group's best efforts, they could not pinpoint the fourth member of their team. The party contacted 911 via a satellite device, and Kittitas County Search and Rescue responded to the area on Friday evening. Additional rescue efforts were postponed until daylight. Search and Rescue then returned to the site on Saturday and were joined by NWAC forecasters. The teams were able to locate the remaining victim. Unfortunately, neither of the fully buried skiers survived. Our deepest condolences to the family, friends, and community of those involved in this avalanche accident. S-SE aspect, 6200ft, Avg Depth 2ft, HS-AS-R3-D2.5-O

Forecast Discussion: 

An unusual atmospheric river is impacting us right now. Northerly parts of the Cascades are getting hammered, while very little precipitation is falling farther south. Hence, the unusual spread of color on the NWAC map. 

 The West North zone is taking the brunt of the water, with over an inch falling Sunday night. Forecasts show it will mainly fall as rain to the top of our upper elevation band. We'll get similar amounts of rain on Monday, with even higher snowlines. If someone is really getting after it, they might find dry (er) snow and reactive storm slabs way up high on Monday. It will remain windy. After this event is over, expect an extended period of warm weather without precipitation. 

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