Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Rain, warm temperatures, and sunshine by Tuesday afternoon will create dangerous avalanche conditions above 6000ft near the Cascade Crest. Wet avalanches could grow large, cornices may fall, and the snowpack will need time to adjust to the rapid thaw. Build in a wide margin for error and choose conservative, low-angle terrain.

Problemi valanghivi

  • Loose Wet

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

    Light rain may continue to fall overnight Monday to the highest elevation peaks. Expect cloudy skies early Tuesday as conditions dry out, with increasing sunshine in the afternoon as freezing levels skyrocket to 10,000ft. As the recent dry snow becomes wet and saturated it will rapidly lose strength. Wet loose avalanches could gouge into the snowpack, build significant mass, and run far downslope. When you find wet sticky snow or see new avalanches, dial it back and stay off of and out from under steep slopes. We expect most of the natural avalanche activity to stay small, but you could see a larger avalanche in big complex terrain at upper elevations where more snow accumulated over the past few days.

    Example photo of rollerballs and developing wet loose issues we expect for Monday Photo: Andrew Kiefer

Avalanche Discussion

Observers throughout the region enjoyed their last powder turns early Monday before snowfall transitioned to rain. The warm-up caused widespread wet loose activity near and below treeline in the East South's neighboring zones. Storms since Friday brought up to 1ft of cold dry snow with precipitation favoring areas above 6000ft near the Cascade Crest. The more recent cold powder, the more snow there will be to entrain as wet avalanches run in the coming days. Wet avalanche activity may peak during the rain overnight Monday, or could be ongoing with warming and sunshine throughout the day. Cornices may also fall on slopes below acting as huge triggers. The snowpack will need time to adjust, and Tuesday will not be a day to mess around if you venture out into the backcountry. 

NWAC staff traveled in the Ahtanum Meadows area on Friday (Observation). Rounding facets were identified overlying the Early March Crust, which was buried about 11-15 inches deep. Both natural and human-triggered avalanches were observed that failed on this layer 3/16-17. Although avalanche activity on this layer so far seems to be isolated to areas where the wind has drifted the snow into deeper slabs, it could become a more widespread problem with the rain, warming, and sunshine the next 24 hours.

The East South zone is certainly not breaking any records for snowpack depths this winter. The warm temperatures associated with recent storms kept snow accumulations minimal at elevations below 6000ft. Below treeline areas have very little or no snowpack and many southerly aspects are melted out to ridgetops. Utilizing roads and summer trails to access higher elevations with a more robust snowpack is the best option. Travel cautiously, especially at lower elevations, to avoid impacts with rocks or stumps, and beware of open creeks.

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