Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Wet avalanches in sun exposed terrain are possible with clear skies and warming. Move off and away from steep slopes if the snow surface becomes unsupportable.  Limited observations above treeline will require you to assess conditions as you ascend.

Problemi valanghivi

  • Loose Wet

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

    Natural and human triggered loose wet avalanches are possible in sun exposed terrain. Layers of drier new snow at the surface at and above treeline will be more susceptible to warming than rain saturated snow at lower elevations. Move to shaded terrain if you are sinking into wet, unconsolidated snow or witness signs of instability like rollerballs or recent avalanche activity. Plan on limiting travel directly under steep south facing terrain in the afternoon. Loose wet avalanches are unlikely if the snow surface is frozen or partially melted.  Be wary of cornices and other overhead hazards more likely to fall down with rapid warming.

    (3/3/2022)

    A large natural loose wet avalanche from Monday Feb 28th. This slide nearly crossed a very common exit trail from the Alpental Valley in Snoqualmie Pass. 

    Photo: Alpental Ski Patrol

Avalanche Discussion

Periods of visibility in neighboring zones allowed observers to document extensive avalanche activity from earlier in the week. Crowns showing wide propagation and step-downs in bed surfaces show that avalanches were broke into deeper layers around the February 14th crust. Continued avalanche activity associated with rain and wet, unconsolidated snow conditions tapered off today with slightly cooler temperatures and diminishing precipitation. A few loose wet avalanches to D1 were observed during sun breaks on solar aspects and mostly involved only the top layer of new snow. No new avalanches were observed in older wet snow layers on test slopes or other steep features.

Weather station data points towards the conclusion that West Central received more rain than snow at below and near treeline elevations during the parade of storms last week. While areas farther north continued to accumulate new snow and will likely see a bigger loose wet cycle in new snow layers, this zone likely saw the peak of loose wet activity during rain events. The outlier to this is at the highest elevations that have many feet of deep snow and should be reactive to a few rounds of strong sun plus higher afternoon temperatures.

 

 

 

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