Bollettino valanghe

Bollettino valanghe

Payette Avalanche Center
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Pericolo valanghe

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

In sintesi

Merry Christmas! Dangerous Avalanche Conditions Exist in wind-loaded, upper elevation, steep terrain!

Gusty 30-40 MPH winds Thursday and winds through Saturday evening, along with upwards of 2 feet of new snow have and will continue to load leeward terrain and likely form more sensitive wind slabs.

Loose-dry snow will be adding up enough to move on steep slopes as you ride or ski. Sluff management and good travel protocols are essential!

If you are seeing red flags like fresh avalanches, shooting cracks, or hearing hollow sounds or loud whoomphing noises, find another route.

Be cautious in and around steep slopes...Avoid slopes steeper than 30 degrees that have been loaded or cross-loaded by the wind.

Problemi valanghivi

  • Wind Slabs

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

    2 feet of new snow and light winds over the next 24 hours could form some fresh slabs on top of what seems like a glued event when strong Southern winds moved snow Thursday making upper elevations almost unbearable.  Now temps have dropped and more snow and gusty winds are forecasted today...Avoid Steep upper elevation Wind Loaded slopes!

    Careful route finding is going to be essential today. Watch out for signs of wind on the snow surface like etching and drifts to help figure out exactly where the wind deposited snow. Most of the wind has been SSW which will load Northern aspects mostly, but local terrain can influence, or change the direction of loading and wind slab formation. 

    If you are seeing red flags like shooting cracks or hearing hollow sounds or loud whoomphing noises, find another route.

    Winds at the Granite weather station on Thursday were strong, now they are ramping back up again.

  • Loose Dry

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

    Temps are cooler and the new snow that is forecasted to come in over the next 48 hours will be adding to the depth of the unconsolidated surface snow. Loose snow can run downhill and entrain more as it moves which can push you into bad places like rocks and over cliffs.

    The steeper the terrain, the more exposure, and the length of the slope will add to the danger of the loose snow problem.

    Sluff management and general situational awareness are going to be a good practice as the snow stacks up.  Spread out, keep your eyes on your partners, and travel 1 at a time on slopes steeper than 30 degrees.

Avalanche Discussion

Thursday the temps warmed up and we saw some impressive winds that were moving snow. Tamarack ski patrol reported that they got results with explosives, ski cutting, and stomping cornices within the upper foot of the snowpack. I was able to get a shooting crack on an edge of Wildwood bowl that was actively getting wind loaded.

Christmas day and evening Santa is making it snow anywhere from a foot to 2 feet and blow moderate winds out of the South/South-west . Watch out for signs of wind on the snow surface like etching and drifts to help figure out exactly where the wind deposited snow. Most of the wind has been SSW which will load Northern aspects mostly, but local terrain can influence, or change the direction of loading and wind slab formation. 

Loose dry snow will be stacking up giving face shots and running down the mountain with you. Sluff management is going to come into play...if you get a lot of loose dry snow moving with you you could get pushed into terrain that you are not wanting to enter like rocks, gullies, and cliffs.

*While we know that the winds are forming slabs on the surface in leeward terrain, the formation of denser snow on the surface has happened as the temps have warmed. In areas that were protected from the wind, a storm slab has likely formed (denser snow near the surface with new lighter snow covering it up).

Be suspect of slopes steeper than 30 degrees, and use good travel protocols like exposing only 1 person at a time to avalanche terrain.

Coverage for over-snow travel is getting better, but be constantly cautious of hitting wood and rocks. Be careful and patient, it is getting deeper every day.

Our snowpack is coming along nicely and is pretty right-side up. Our persistent problem, Facets, and crusts that are the make-up of our early Oct-early December snowpack are slowly rounding and getting stronger and getting buried deeper.  Our test results have been good and strong on the lower old snow, and moderate failures that lack propagation in the upper snowpack.