Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The storm is slowing down, but avalanche danger remains Considerable, and human-triggered avalanches are likely. Avoid all steep slopes, and remain cautious in lower-angle terrain beneath steep slopes at all elevations. Travel through runouts beneath steep slopes quickly, or avoid them altogether if you see any new avalanches or other signs of instability like continued intense snowfall and wind. 

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–3

    The storm is tapering off on Thursday, but with recent intense snowfall and extreme wind, remain on alert. Avoid all steep slopes. If you have any doubt, consider steering around, or travel quickly, through lower angle terrain beneath steep slopes as well. If you see or trigger any new avalanches, see any long shooting cracks or experience any whumphing, avoid all avalanche terrain. 

    Stability may improve throughout the day, but it will be difficult to actually identify any changes. Weaknesses will likely stay hidden, as the slab of highly wind-affected new snow is very thick. You may not notice anything is wrong until you get out onto a steep slope and trigger a large, unsurvivable avalanche. Don't push it into steep areas as the day progresses - we need to give this several-foot snowstorm time to settle and stabilize. 

    Example photo: a slab avalanche like this one may surprise you on Thursday.  Photo: Andy Berner

Avalanche Discussion

Neighboring zones have found some locations where a weak layer of facets exists above the Early February Crust, which is about 4-6ft below the surface. This weakness is probably inconsistent, but may exist in some areas. If you trigger an avalanche on this layer, the avalanche will surprise you by spanning wider and deeper than any other avalanches, and it will be very large. In both the Highway 2 corridor and the north side of the Mountain Loop Highway in the last week I investigated this weak layer and didn't find it. In both locations I dug at 5300ft on a north facing slope. 

White Chuck's total snow amount went up 39 inches in the last 4 days as of Wednesday night. Other precipitation gauges throughout the zone have gained more than 5 inches of water since Saturday, which is probably at least 4 feet of snow.  On top of this, about 1 1/2ft of snow is forecasted to fall Wednesday night before snowfall backs off, and then we'll probably get about 3 inches during the day Thursday. Winds will transition from extreme to moderate. This doesn't mean it's a free for all on Thursday, as the snowpack needs time to adjust. 

With 4 to 6+ feet of new snow throughout the zone by the time this storm winds down, make sure you're aware of tree well and snow immersion suffocation (SIS). Aside from trees, creeks and other holes are sneakily buried up to at least 5000ft and there's a high risk of falling into them. 

If you make it into the backcountry, please share with us what you saw by submitting an observation. 

Regioni coperte