Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The cold and snowy pattern continues. Heightened danger could be found at higher elevations, where the new snow is deeper and you're more likely to trigger a slab. Loose dry avalanches may entrain a surprising amount of snow on steep slopes at all elevations. Look for signs of instabilty like recent avalanches, shooting cracks, and whumpning collapses and choose terrain cautiously. 

Problemi valanghivi

  • Wind Slabs

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

    Avalanches could be larger at upper elevation where wind has sifted the snow enough to be a cohesive slab. Easterly winds blew on the 27th, and may have created slabs on open exposed terrain. With some new snow, these slabs may get buried and obscured so they could be difficult to identify. On Tuesday, the winds shift back to westerly, and could create fresh reactive soft slabs near higher ridgelines. Watch for drifts forming on cross-loaded features and gullies. Steer around large and obviously wind-loaded terrain right near ridgelines and cliffs, especially if you find shooting cracks, whumphing collapses, or strong over weak structure. 

    Carefully assess the bond at recent interfaces, and how it changes as you travel. Use small test slopes and quick, informal tests to see how the snow reacts.

    (2/23/2023)

    Cracks break through wind-drifted slabs on a southeast aspect near treeline near Whistler peak.

    Photo: Will Govus

  • Loose Dry

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

    As cohesionless snowfall accumulates, you might find that dry loose avalanches become frequent on steep slopes. These could entrain a fair amount of low density new snow, and pile up to be deep in some areas. At lower elevations they could run on older weak snow surfaces and firm crusts. Larger and steeper pieces of terrain could produce slides that pack more of a punch. Especially be careful of rock walled couloirs, gullies, and similar places where debris ends up.

    An example of loose avalanches and overhung cornices in the Cutthroat drainage from a previous season. Photo: Josh Hirshberg

Avalanche Discussion

The upslope nature of the past few rounds of snow have likely favored mountains in the eastern half of the zone. Observers are reporting about 12" of new snow since Sunday, with about half an inch of water equivalent. Winds have been switching direction, and will switch from east back to west early on Tuesday. Prior to Monday, a few rounds of moderate, and sustained southwesterly winds were recorded at Washington Pass. On Saturday, observers triggered a small wind slab avalanche that entrained loose snow on a northeast aspect around 8,000 feet of Kangaroo Ridge. On Friday, a group triggered a nearby large cornice fall after they felt a collapse while standing on a ridge near Tower Mountain.

You'll generally find a crust from early February from 1-2.5ft down, depending on elevation, aspect, and proximity to the crest. This crust can be found up to at least 7,000ft, and is shallower at lower elevations and further east in the range.

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