Bollettino valanghe

West Slopes North

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Avalanche danger will increase through the day as a strong storm moves into the region. Expect gusty winds and all-around stormy conditions. Default towards simple, sheltered slopes. Assess new snow instabilities if considering steeper, more exposed terrain.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Snowfall amounts could vary greatly across West North and end up being much more - or much less - than forecast. Look for 4-8” of new snow and a gradual warming trend taking hold by day’s end. Wind speeds are more certain with strong to extreme winds occasionally reaching down into low elevation areas and drifting freshly fallen snow.

    You will be much more likely to find an unstable slab on wind load slopes, but assess for instability in sheltered terrain as well. Slabs are more sensitive to triggering where they form over surface hoar or weak facets that have survived on shaded slopes.

    Start the day with an assessment mindset and test the waters with small slope cuts and hand pits before moving into bigger terrain. Be ready to find more instability in the afternoon than what was found in the morning. Stormy conditions might just keep you in the most sheltered areas for the entire day. Mid elevation danger could exceed Moderate in some areas.

    (2/9/2025)

    Small wind drifted features provide a safe, easy way to test how sensitive fresh slabs are to triggering.

    Photo: Kyle Wyatt

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Rising snow levels should moisten freshly fallen snow and might even switch over to rain. While any avalanches that do release should be small, they can still be consequential in low-elevation terrain with gullies, creeks, or other hazards in the runout. The first signs of wet avalanche instability would be snow shedding from trees, rollerballs, and very small avalanches.  Look for wet avalanches at mid-elevations if snow levels end up higher than forecast.

    (2/4/2023)

    Rollerballs are an initial sign that soft snow is warming and more likely to produce an avalanche.

    Photo: Ian Nicholson

Avalanche Discussion

Friday was likely the last day of Low danger and calm weather for a bit. Obesrvers in the Baker Backcounty and Anderson-Watson near Baker Lake reported minimal avalanche hazard, but the next storm is definitely on the doorstep with increasing winds late Friday afternoon. In general, cooler temps, less sun, and a hard crust on southerly aspects nearly eliminated the threat of additional wet avalanches.

While wind slabs were stubborn to unreactive in most parts of the forecast zone, fresh wind slab avalanches were observed at Cascade Pass on Thursday (photo). It's likely that there was just more snow available for transport as that area saw slightly colder temperatures that better preserved soft snow at the surface.  Higher wind speeds and much bigger, alpine terrain were undoubtedly the other part of the equation.

The biggest snowpack factor that affects future stability is the current surface. While any slope getting sun has seen repeated warming and formed a crust, northerly aspects are holding onto facets or surface hoar. How well these weak surfaces survive strong winds  - before they have a chance to get buried by new snow - is something to keep an eye on . 

Regioni coperte