Bollettino valanghe

West Slopes North

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Wednesday will not be a typical sunny day after a storm. A late-morning shift from winter back to spring plus overlapping avalanche problems will require vigilance as conditions change. Deep new snow will react to rapid warming and produce avalanches. Choose terrain with plenty of options that allow you to easily avoid avalanche terrain- avalanche danger should reach High by late-afternoon.

Problemi valanghivi

  • Loose Wet

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

    Despite a cold start to the day, strong sun and a rapid rise in temperature will create wet avalanche problems before the latest storm and wind slab layers even have a chance to settle out. It’s pretty simple - there is 5’ of new snow and it just won’t play nice once it gets overheated. It’s a sure bet we will see natural wet loose and other avalanches related to warming by the afternoon. The questions that remain for tomorrow are:

    • How many will there be? On most steep slopes or just the usual locations under cliff bands, etc?
    • How big will they be? Large (D2) or smaller (D1)?
    • Will they occur on all aspects or just those getting direct sun?

    Right now we believe these slides will be most common on very steep and often sunny slopes. While they may grow large enough to kill you, they should not run far distances. Ultimately it going to be up to you to monitor conditions throughout the day and gauge how fast the mountains are coming unglued. Given all the unknowns about the extent of natural avalanche activity, it’s probably best to play it safe. When the snow becomes wet and saturated or you see signs of instability like rollerballs and small wet avalanches then it's probably time to move to simple terrain with no exposure to avalanche terrain overhead  - or simply go home

    (3/13/2022) Wet loose avalanches on Shuksan Arm in March

    Photo: Jason Speer

  • Storm Slabs

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

    New storm and wind slab layers should be less reactive tomorrow but the quantity of new snow still requires caution. The greatest danger of triggering a slab avalanche will be on steep wind loaded slopes where slabs will be reactive for longer. As the day grows warmer all slopes could see an uptick in danger as the surface layer warms and becomes more dense over colder, weaker snow below. Cornice fall and wet loose avalanches could serve as large triggers than could pull out a slab where the weight of a single person may not. 

    The best plan for Tuesday morning will be to travel on slopes less than 35 degrees to reduce uncertainty. As the day gets warmer and the sun does its work start reducing your exposure to steep terrain overhead as well.

    (4/5/2022)

    Large slab avalanche on Huntoon Point. Northeast aspect  at ~5000'.

    Photo: Mike Elges

Avalanche Discussion

Skies cleared on Monday afternoon and allowed observers to see the extent of natural avalanche activity from the last few days. While some slopes showed little sign of activity, storm and wind slab avalanches up to D2 were observed on Huntoon Point and Mt. Herman with more seen in above treeline terrain high on Shuksan. In general, the new snow is right side up with wind loaded terrain holding more of a slab as usual. Test slopes produced mixed results today with many of them showing little cracking and propagation while a few others cracked the full depth of the storm snow. 

Freezing levels and temperatures are forecast to climb even higher on Thursday reaching 10,000' by that afternoon with high temperatures pushing 50 degrees. One of the simplest adages in the avalanche world is snow doesn't like rapid change - well, rapid change is here for the next few days. As the mountains warm even more we expect to see avalanches grow larger in size and run to lower elevations. Cooler conditions going into the weekend should sharply reduce the danger from wet avalanches. 

Regioni coperte