Bollettino valanghe

Bollettino valanghe

Payette Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The Avalanche Hazard is Moderate today in wind exposed terrain.  You are likely to encounter newly formed wind slabs near ridgetops and in leeward terrain.  Winds have shifted around the compass this week so you may find wind slabs on multiple aspects ranging from a few inches to close to 2 feet thick. Wind speeds this week gusted into the 32 MPH range and easily transported the light-density snow that we received. You are also likely to have surface snow moving with you in the form of shallow sluffs if you are skiing in steeper terrain.  Lower elevation, protected aspects have generally stable conditions but several weak layers are distributed in these areas.  Until we see significant accumulations, these layers are unlikely to produce avalanches or will be confined to small slabs in the upper 6-10 inches of the snowpack.  Riding and sliding conditions are very good although there are still some lingering areas of breakable crust hiding under the new snow on the solar aspects. Use good travel protocols especially in steeper terrain.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Winds speeds have gusted around the compass this week and with 11 inches of new, cold, light density snow, the wind speeds were more than adequate to build wind slabs near our ridgetops.  Most of these slabs are confined to areas near the ridgetops but are widely dispersed across multiple aspects.  You are more likely to trigger these slabs near ridgetops or just below them on steeper terrain.  In addition to the wind slabs, you are likely to find a very stout windboard( crust) near the ridgetops or on prominent sub ridges that were exposed to the higher velocity wind gusts.  Visual clues of wind effect are getting covered up with the snow we received Wednesday night and through the day yesterday but some of these slabs had a distinctive hollow sound when we were crossing them.

    Visual evidence of wind-affected snow on and near ridgetops. Etching, drifting, and sculpting are signs of wind slab formation.

Avalanche Discussion

Today's advisory is possible through the generous support of CM Backcountry Rentals and Adventures. 

This week's series of small storms have been a welcome addition to our snowpack and provided a great refresh to the riding and sliding conditions.  Wind-protected slopes have plenty of soft snow on them and good snow can be found on upper elevation slopes that have been protected from the worst of the winds.  Ridgetop and near ridgetop conditions are a mixed bag and also where you are most likely to encounter wind slabs that will be touchy for skiers and snowmobilers. Most of these new wind slabs are relatively shallow but you might find some pockets that are getting close to 2 feet thick.  Without much new snow in the forecast and a return to high pressure, these slabs should start to stabilize over the next few days.  

Light, dry snow like what we have out there now also wants to sluff or run with you when you are on steeper terrain.  Snowmobilers and skiers/boarders should plan on this moving snow and make sure it isn't going to push you where you don't want to go. 

Protected areas are holding the best snow but also are accumulating weak layers that are slowly getting buried.  You will find a layer of mixed type, faceted, snow  around 6 inches down just below a subtle humidity crust and a layer of large graupel(in some locations) below the new storm snow (around 12 inches down).  There is also a deeper weak layer that is less reactive in our pits but still notable given the strength of the snow above and below it.

Overall, conditions are pretty incredible on anything but due south terrain where you will still find the sun/melt-freeze crust under the new snow. This should be a great weekend to enjoy some prime conditions in the mountains.

Even in moderate and lower hazard conditions, avalanches are still possible in specific locations,  good travel protocols and a one at a time policy on steeper slopes is your best insurance as you travel and play in the mountains.  

Also, as we all search for fresh snow please take a few minutes to review the Payette Winter Travel Map, there are some areas that are closed to motorized travel and are not signed.  It is your responsibility to know where these areas exist and respect closures for wildlife and non-motorized users.  Some of these closures are near Jughandle Mountain, Brundage Mountain Ski Resort, and Goose Lake, other closures exist in the Lick Creek Canyon.