Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The warm temperature trend will continue for Thursday, so expect wet loose avalanches to become problematic during the day. Look for rollerballs, wet punchy snow, and recent wet avalanches as indicators that you could trigger them. Use caution on, or move away from slopes steeper than 35 degrees when you notice these signs of instability.

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    A second day of very warm temperatures will keep wet loose avalanche activity going. Sunshine and warm temperatures will quickly melt snow surfaces on Thursday. Expect that these may become problematic as the daytime warms. Look for indicators of wet activity such as moist surface snow, rollerballs, and recent fan-shaped avalanches. Once you notice these, or if you begin to sink into wet snow deeper than your boot top, its time to get off of steep slopes. The potential size of loose wet slides will increase where you find more recent snow especially as you go further west in the zone. While loose avalanches are predictable, they may grow larger and could be dangerous in consequential terrain and near terrain traps. 

    Expect at least some activity on slopes that were previously dry like west to north to east aspects below around 5,500ft. Directly north facing slopes at higher elevations may stay cooler.

    (3/31/2021) A wet loose avalanche (D1.5) off northeast facing terrain near treeline above Tumwater Canyon.

Avalanche Discussion

Thursday will be another day of very warm temperatures, and overnight refreezes may be minimal. Expect snow surfaces to melt quickly with the rapidly warming temperatures. On Wednesday, temperatures were very warm, but morning temperatures were quite cold, and wet activity may have been delayed because of this. On Tuesday skiers could initiate very small loose wet slides and rollerballs on steep east and south-facing slopes near Mission Ridge with daytime warming. Wind slabs were well bonded, and were not reactive to ski triggering. This could be different on the higher peaks and closer to the crest where more snow fell. A warming trend will continue to destabilize the new snow as it transitions from dry snow to wet snow on Thursday.

A strong winter storm brought heavy snowfall late on Sunday with strong to extreme westerly winds. Snow totals by Monday were: Trinity Snotel 8", Fish Lake 13", Sasse Ridge 10". Winds gusted to 70mph on Dirty Face and over 100mph at Mission Ridge.

The lower snowpack is generally well settled, although a layer of facets above and below a crust from mid-January created prolonged avalanche activity through February. Although we don't have any observations of avalanches on this persistent weak layer since March 1, it is worth keeping on your mind as we transition into spring. The persistent weak layer can still be found about 2-6 feet below the surface throughout most of the zone. The most suspect areas for any deep persistent slabs at this point would be unsupported, shallow and rocky slopes that sit in the sun. 

Régions couvertes