Bollettino valanghe

West Slopes South

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

A warm and wet storm will cause avalanche conditions to deteriorate significantly throughout the day and eventually result in natural slides. These will be the largest and most dangerous higher in the terrain. Limit your exposure to areas where avalanches can start, run, and stop. 

Mt Saint Helens and Mt Adams could see very dangerous conditions throughout the day.

Problemi valanghivi

  • Storm Slabs

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

    Warming temperatures will turn the snowpack upside-down smearing thick heavy snow over the much drier snow from the weekend. This will likely result in slides that are easy to trigger. Eventually, we expect the scale to fully tip and natural avalanches to occur. For most locations, this will be Tuesday night. 

    Basically, this isn’t your normal storm slab day. Sure your uptrack tests, hand pits, and small slopes will give you an idea of how the surface snow is changing and responding. Unfortunately, you’ll need to consider the snow all the way down to the start of the storm (12/13). Avalanches could fail on any number of layers or entrain soft snow and grow bigger. 

    Given this setup, choose simple terrain and be ready to dial it back further as the storm starts to warm. Ultimately, you’ll need to avoid avalanche terrain entirely as things get really scary.

    (12/14/2024)

    This is one of several avalanche involvements in the storm snow from the weekend.  

    Photo: Jeremy Jouppe

  • Loose Wet

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

    Rain and wet heavy snow should reach into the lower and possibly middle elevations at some point in the day. This should turn the recent dry snow into a dangerous issue. Expect natural wet avalanches. Most of these should remain small, but you could encounter a few larger ones. Fortunately, the travel advice is the same. Once it starts to warm, find ways to stay away from and limit your exposure to steep open slopes.

    (1/14/2023)

    Example: A larger wet avalanche from a similar rain on snow event during the 22/23 season. 

    Photo: Dallas Glass

Avalanche Discussion

This storm is messy and the timing is quite uncertain. A significant warm-up is on the way bringing rain very high into the terrain. Different parts of the zone will likely reach the tipping point into natural avalanche activity at different times. Mount Saint Helens and Mt Adams will see temperatures rise first and could see the highest snow levels. Very dangerous conditions could develop there during the day. Mt Rainer should be next. Lastly Crystal and White Pass might not hit the brink until the overnight hours. Those times are just our best guess. With so much uncertainty, don’t get too committed or super far from the trailhead.

The recent storms have brought 18-24 inches (45-60cm) of snow and counting since Friday (12/13). Human, natural, and explosive triggered slides have been reported near Crystal, Mt Adams, Mt Rainier, and Mt St Helens. On Monday, NWAC forecasters near Crystal continued to experience short shooting cracks and found facets at the 12/13 interface. All of these signs point toward conditions continuing to shift towards the much more dangerous end of the spectrum. 

Coverage continues to improve around the zone, but creeks, small trees and bushes continue to be an issue.

Regioni coperte