Bollettino valanghe

Blues

Wallowa Avalanche Center
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Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
Senza grado
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Continued warm temperatures,  the lack of overnight freezing temperatures, and expected rain on snow will make wet avalanches likely in steep terrain.  These avalanches could fail as loose snow avalanches or as slab avalanches.  Avoid being on or under avalanche terrain until freezing temperatures return. 

This forecast is sponsored by Anthony Lakes Mountain Resort.

Problemi valanghivi

  • Loose Wet

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

    It has been over a week since weather stations in the Blues have seen freezing temperatures.  This has melted snow in the upper snowpack and water has dripped through the snow until it has reached a crust buried in the upper 2 feet of the snowpack.  This has created unstable upper snowpack conditions.  Until we see a solid freeze at night coupled with lowering daytime temperatures, it will remain likely to trigger wet loose avalanches in terrain steeper than 35 degrees.

    The onset of rain on the snowpack today will increase the likelihood of wet avalanches.   Even a smaller wet loose avalanche has the potential to knock you off your feet and carry you over consequential terrain or push enough snow into a terrain trap to bury you.  

    In your travels in the mountains today, pay attention to how wet the snow is under your feet or machine.  Get curious and dig down a few feet and see how wet the surface snow is as well as how deep water has percolated in the snowpack.  If you step off your machine or boards and are sinking up to your boot tops in wet snow, it's time to head to terrain less than 30 degrees in steepness.  

    Example of Wet Loose avalanches in the Southern Wallowas 

    Photo: Caleb Merrill

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2.5

    The big scary step up from wet loose avalanches is wet slab avalanches.  As more water is introduced into the snowpack as rain, it can percolate down to buried weak layers or crusts and fail in the form of a destructive wet slab avalanche.  I wouldn't rule this out today if we see the upper end of the precipitation forecast.  Weak layers in the form of buried surface hoar 1 foot down and the 2/1 Rain Crust 2-3 feet down have been found in the Blues.  You don't want to get tangled up in a wet slab avalanche and avoidance of traveling in steep terrain is the best tactic as their timing are notoriously hard to predict.

     

    (3/13/2024) Photo: Wallowa Avalanche Center

Avalanche Discussion

The snowpack has undergone a big change in the last week in the way of very warm temperatures and freely moving water in the upper snowpack.  Colder temperatures and more snow are on the horizon, but we are not out of the woods!  Stay vigilant in your mountain travels and snowpack assessment.  Make a conservative travel plan to avoid areas where you have a higher level of uncertainty of the presence of persistent weak layers.  Avoid wet sloppy snow conditions as this is where wet avalanches are more likely to occur. 

The recent warm spell has destabilized cornices to the point that they could break naturally or as you step or ride near them.  Check out Wallowa Alpine Huts guide Killian Sump's observation here that notes several natural cornice failures and a recent slab avalanche in the Southern Wallowas.  Give cornices a "wider than you think" buffer.  

If you are out and about in the Blues, submit an observation of what you are seeing here.  I'll be traveling there today and provide an update on what I am seeing.  

No danger rating has been issued for the lowest elevation band in the Blues (3000'-4000') due to the lack of snow in that zone. If we receive significant low elevation snow we will begin forecasting for that zone again.

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