Lawinenlagebericht

West Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

The mountains are coming out of a major storm. Stick to lower-angle terrain to reduce the risk of triggering an avalanche. Look out for wet avalanches if the sun makes an appearance. Give large and looming cornices plenty of space as it warms up through the week.

 

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Continued snowfall should put down another 2-6" by Tuesday morning. The overall likelihood of triggering or being caught in a slab avalanche is decreasing. Conditions are still considered dangerous given the amount of new snow since Sunday and continued wind loading at upper elevations.

    You are more likely to trigger an avalanche on slopes with recent wind loading. Warming could increase the chance of triggering a slab as well.

    Test slopes and hand pits are useful for evaluating the upper layers of new snow. They won’t tell you much about the old/new snow interface that is 2-3’ down at upper elevations. The easiest way to reduce risk is to limit travel on large steep slopes or smaller slopes with consequences like trees or gullies in the runout.  

    Storm slab avalanche from earlier in the winter in Canyon Creek/West North.

    Photo: Jeff Hambleton

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    There is no shortage of fresh, new snow out there. If the sun comes out for real anticipate significant wet loose avalanche activity. Though initially small, wet avalanches can grow large or trigger a slab avalanche lower on the slope or run farther than expected.

    Look for initial signs of instability like snow shedding from trees and rocks - which are hazards themselves. Pinwheels or balls of snow rolling down the slope are also telltale signs of warming. If you see these it would be a great time to give a wide berth to slopes facing the sun. 

    The likelihood of seeing wet avalanches is a contest between how fast low clouds clear out in the morning versus how fast high clouds move in later in the day. If it stays cloudy there shouldn't be many avalanches. 

    A D2 (large) wet snow avalanche from earlier this winter.

    Photo: Irene Henninger

Avalanche Discussion

Avoid traveling directly under large cornices that probably grew even larger in the last 24 hours if they haven’t fallen off already. A falling cornice can also trigger a large slab avalanche where a single person or even a group of people would not. 

West Central got quite a soaking with many weather stations reporting 2.5” to 3.5” of precipitation or snow water equivalent. While this fell as rain below treeline, it likely produced significant new snow at upper elevations. White Chuck, farther inland east of Darrington at 5000', picked up 12” or more inches of new snow that fell at just below-freezing temperatures. No avalanches were reported but this is probably more due to people avoiding backcountry travel than a lack of natural avalanche activity.

Similar precipitation was reported from West North with avalanche control work producing slab avalanches 1-2' deep. Less precipitation, snow, and avalanche activity were reported from Stevens and Snoqualmie Pass. Wet avalanche activity was seen in both zones, especially Stevens Pass where a brief period of sun produced natural avalanches to D1.5 in size.

If you get out Tuesday submit an observation and let us know what you see. 

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