Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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In sintesi

An atmospheric river delivering snow and rain will create dangerous avalanche conditions. Avalanches large enough to kill you are very likely. Choose mellow meadows at lower elevations well away from the bottom of large avalanche paths if you plan to brave the rain on Sunday.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1.5–2.5

    Freezing levels are forecasted to be around 6000 ft but as with any forecast, they could end up being higher or lower, changing where precipitation will fall as snow or rain. Ultimately, regardless of whether you make it through the wet snow to reach dry snow somewhere higher up, conditions will not be safer. This atmospheric event (AR) will test buried weak layers at all elevations with added weight to the snowpack. Areas further west in the zone will receive higher snow totals, making conditions especially precarious in these areas.

    Persistent slabs can break in surprising ways and wider than expected. You will be more likely to trigger a slide in wind-loaded areas, so be on the lookout for signs of wind transport. Clear signs of instability are cracks shooting from your skis or machine, collapsing (whumpfing), and recent natural or triggered slab avalanches. The best way to manage this problem while we wait for the snowpack to adjust to its new load is to avoid avalanche terrain. This includes where avalanches can start, run, and stop.

    (2/21/2025)

    A small skier triggered slab avalanche made clearly visible the two weak layer interfaces in the snowpack right now.

    Photo: Payton Schiff

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1.5–2.5

    Wet slab, persistent slab, wet loose, even glide...whatever you want to call them, the fact is liquid water will be introduced to the snowpack, rapidly increasing the likelihood of avalanches. You're not going to want to hang out on or below large paths where slides could grow large enough to bury or kill you. Cornice could sag and collapse, so be wary of precariously hanging blocks of snow that might break above or below you.

    Until water has time to drain out or refreeze, avalanches will be of concern. Don’t linger in terrain traps where avalanche debris can concentrate, and be aware of steep terrain overhead where avalanches can start.

    (12/29/2024)

    The debris pile of a large wet snow avalanche from earlier in the season on the West Face of Teanaway Mt. 

    Photo: Rob Pollard

Avalanche Discussion

We have good confidence that the January Drought Layer (JDL) is generally relegated to only NW-N-E aspects at upper and middle elevations. There is less confidence about the distribution of the 02/13 interface. With such a significant storm impacting the zone, we can't say with certainty any steep slope will be particularly safe on Sunday.

The timing of natural wet slab avalanches is nearly impossible to predict. Most of the rain will fall overnight Saturday into Sunday and the highest hazard will probably be during this time period. There will be a break in the action and then heavy precipitation will return around 1 pm. It might take this next wave of rain to unglue or something, or it might not. With such uncertainty, expect avalanche hazard to be high all day.

In general, we don't think lower elevations have the volume and snowpack structure for a widespread, dangerous avalanche cycle. However, nearer to the Cascade Crest, there is a chance that avalanches could run all the way down to the valley bottom. More rain will fall further west in the zone, and there is more snow on this side of the zone to be influenced. It will be likely that you'll see quite a few smaller wet loose avalanches at this elevation band zone wide.

Ultimately, it's not worth your skin to enter avalanche terrain on day like this.

Regioni coperte