Bollettino valanghe

Bollettino valanghe

Payette Avalanche Center
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Pericolo valanghe

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

In sintesi

6-12" of recent snowfall accompanied by strong W/SW winds have created sensitive slabs at all elevations. This dense snow is overlying soft, weak snow from recent weeks. With a load of new snow, triggering a persistent slab avalanche remains possible, especially in the southern end of our advisory area.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    This persistent slab problem has been mainly confined to the southern end of our advisory area (areas near West Mountain). Within the past week, we've found persistent weak layers within certain pockets at other locations within our advisory area. Before yesterday's storm, this problem was becoming unlikely. 6-12" of snowfall yesterday and strong winds have added additional stress to this persistent slab problem and have increased the likelihood of triggering today. You're most likely to encounter this problem on the northern part of the compass at elevations between 7-8000 feet.

     Isolated pockets harboring buried surface hoar or facets are very difficult to find when they are buried under two-plus feet of snow. Recent wind loading has added a significant load to buried weak layers. The best way to manage this problem is to avoid steep, wind-loaded slopes. 

    (3/5/2023)

    The public submitted this observation of a large snowmobile-triggered avalanche. SS-AMu-R3-D3-E-7500'. 

    Photo: Public

  • Wind Slabs

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

    Yesterday, winds were gusting into the 50 MPH range and we received reports of stronger wind gusts around West Mountain. Winds were W/SW for most of the day yesterday. 6-12" of recent snowfall with strong winds created drifts that were 18-24" yesterday afternoon. You are most likely to encounter a wind slab avalanche above 7000 feet, on east-facing slopes, especially just below ridgelines. Yesterday, near Jughandle Mountain, we observed multiple natural avalanches that failed on the new/old interface. All of these avalanches observed were on wind-loaded slopes. However, 40 MPH winds were reported yesterday at elevations below 6500 feet. Recent storm snow was wind-effected at lower elevations than normal.

     Stay alert to red flags like shooting cracks, collapsing (whumpfing), recent avalanche activity, and thick drifts or pillows. These are all signs that unstable snow is present and you should find another aspect and/or slopes less than 30 degrees.

    (3/10/2023)

    7700', E aspect, 25 cm (10") recent storm snow was failing very easily on the interface of recent low-density snow

    Photo: Studley

Avalanche Discussion

Today's avalanche forecast is sponsored by Mile High Powersports of McCall. Thanks for supporting the Payette Avalanche Center.

6-12" of recent storm snow came in heavy yesterday with lots of wind. This new snow fell on 12-18" of soft, settled snow from the recent two weeks. Strong over weak is a basic recipe for unstable snow. Recent storm snow was overloading weak snow in the upper snowpack yesterday. If you were out in the mountains yesterday, you almost certainly experienced what this felt like. We experienced difficult travel conditions while snowmobiling and skiing. Stay alert to signs of unstable snow, especially stiff slabs overlying soft (punchy) snow underneath.