Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Avalanches could be triggered in steep terrain where the wind created deeper drifts and slabs, especially at upper elevations. Avoid steep slopes where you suspect recent wind loading by using lower-angled terrain. Anticipate warmer conditions and the possibility of wet avalanche activity in the days ahead.

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs continue to be triggered in West North, but there have been no observations of reactive wind slab around West Central or Stevens Pass. Still, there is enough snow available for transport and just enough wind you might find one if you look hard enough. Getting caught in a small wind slab could still result in getting pushed into a terrain trap or dragged across rocks, stumps, etc. 

    You are most likely to find this problem along upper-elevation ridgelines, in complex terrain like gullies and couloirs, below cliff bands, or on steep, unsupported slopes. Look for and assess wind-drifted snow as you gain elevation or change aspects.  If you observe more wind than forecast, be prepared to find fresh, reactive slabs that will take a more conservative strategy to navigate safely

    (1/5/2024)

    Signs of wind-affected snow are sometimes more subtle than heavily scoured ridgelines. Textured surfaces, snow/rime in the trees, and drifts behind objects help indicate the wind's direction and what aspects may be harboring wind slabs.

    Photo: Andy Harrington

Avalanche Discussion

Slightly warmer temperatures and clouds on Saturday should lead to much higher freezing levels and direct sun the day following. Avoid being on or directly under steep slopes if you observe signs of instability like rollerballs and very small avalanches, or if the snow simply becomes wet and heavy.

In West North, two new avalanches were triggered on Friday in mid-elevation, wind-loaded terrain. While both were small (D1.5 or less) they show a continued likelihood of finding one in similar terrain. A facet/crust combination was observed as the weak layer and bed surface in at least one of these avalanches.

On Thursday, an observer at Stevens Pass reported 3’ of snow over the ground at 5300’. Wind effect was minimal in this area and no reactive wind slab was observed. The sun had limited effect on the snow surface at midday and good riding conditions were found on south aspects. More warming and melting were reported from later in the day.

Observations from near Hwy 2 in West Central indicated a right-side-up snowpack with minimal instabilities on Monday (observation). There was evidence of previous wind transport along ridgelines.  Small rollerballs were observed on steep slopes in the freshly dampened, low-density surface snow. Lower elevations still harbored obstacles such as exposed or subtly buried stumps, rocks, and creeks.

Regioni coperte