Bollettino valanghe

West Slopes South

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Rain to well above ridge crest will create dangerous avalanche conditions including some natural slides. Expect the hazard to peak during and immediately following periods of heavy precipitation. Dial it back. Steer clear of steep open slopes and limit your time under rocky terrain.

Problemi valanghivi

  • Loose Wet

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

    It’s going to rain. That’s pretty straightforward. We think this will generally result in wet loose slides as the upper snowpack becomes wet and unstable. Sure you may see rollerballs or natural avalanches, but don’t ignore the clue that’s literally hitting you on the head… rain. These won’t be the same easy-to-manage wet loose slides we’ve been dealing with lately. They could gouge, entrain significant snow, and grow large. You could trigger them on most steep open slopes, particularly above 5000ft where more soft surface snow exists. 

    You could also see natural wet loose, wet slab, or maybe even glide avalanches. These will be most likely below cliffs and rocks during and immediately following periods of heavy rain. Look for ways to avoid traveling underneath these slopes. Even as temperatures cool and snow starts to fall, wet avalanches could continue to be an issue until the surface freezes solid.

    (2/11/2024)

    Example: A good sized wet loose avalanche that orginiated in a cliff band. [NE 5650'] You could see similar natural and human triggered slides Saturday.

    Photo: Andy Harrington

  • Wind Slabs

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

    Snow should start to fall sometime mid-day in the higher terrain. We expect it to bond well to the warm, wet surface. However, strong winds could easily form slabs along exposed ridges and below cliffs. Unfortunately, stormy weather will make spotting and assessing wind slabs nearly impossible. Give any steep, potentially wind-loaded slope a wind berth. Head for more sheltered and/or lower-angled slopes.

    (2/22/2024)

    Example: Visual clues of wind loading along ridgelines. These help us anticipate where wind slabs may exist. 

    Photo: Dallas Glass

Avalanche Discussion

At its heart, this is an easy forecast; rain equals unstable snow. However, exactly how the relatively cold, dry, but strong snowpack will handle the rain is much harder to predict. We think most of the activity will only involve the upper 6-8 inches (15-20cm) of softer snow. The much stronger middle and lower snowpack seem well poised to handle the incoming rain. 

In general, the rain should help destroy the pesky surface hoar and near surface facets reported from around the area. However, if places like Crystal Mt or Government Meadows don’t see substantial rain before the cool down, it might survive in pockets throughout the zone. 

With the bulk of the precipitation focussed on the volcanoes, you could see less avalanche activity in areas closer to the crest. Similarly, thin low elevation snowpacks should help limit the danger. 

Ultimately, it’s still early season. Expect open creeks, down logs, patches of bare ground, rocks, trees, and bushes. Once it starts snowing again, some of these obstacles may only hide under a few inches of enticing powder.

Regioni coperte