Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

Heavy snow and strong winds through early Friday will maintain very dangerous conditions and the threat of large natural avalanches once you climb above a refreezing crust. Avoid all open slopes connected to upper-elevation start zones. Near treeline, you can trigger a sensitive wind slab on lee slopes steeper than 35 degrees.

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs formed by strong winds peaking Thursday night and continuing in the moderate range on Friday may be large both near and above treeline. However, they are more likely to overload older, drier snow above the limit of a refreezing crust buried 1/6. This limit should be around 5000-6000 ft. Avalanches originating above this elevation may fracture more widely, entrain more deeply, and run longer distances.  Avoid exposure to any start zone originating above treeline terrain, particularly in the morning when the avalanche danger will be highest. Near treeline, you can use your typical tools to assess potential wind slab danger on slopes steeper than 35 degrees: Recently formed cornices pointing to a suspect slope, lens-shaped pillows, and firm/chalky/punchy snow texture all remind you which slopes to avoid.

    Example: Wind slabs can be firm and chalky in character.

    Photo: Will Govus

  • Loose Wet

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

    A natural loose wet avalanche cycle was well documented and likely peaked Wednesday night and Thursday. With more liquid water hitting the slopes below 4000 ft through Friday morning, loose wet avalanches will continue. Most lower elevation slopes will have at least 6" of moist snow on the surface by Friday. You can easily trigger an avalanche on any slope steeper than 35 degrees that haven't already slid. Natural wet loose avalanches are still possible. While we expect them to be mostly small, some of the natural activity on Wednesday entrained much of the recent snow and could bury a person. As temperatures cool and a crust begins to reform, your danger will decrease and likely end in most areas by later in the afternoon. 

    (1/6/2022)

    Large (D2) Wet Loose avalanche with some slab-like characteristics. Tunnels slide Path. Path terminus at Hurricane Ridge Road around 3000 ft.

    Photo: ONP Rangers

Avalanche Discussion

The threat of avalanche danger will be highest toward the start of your day. It is particularly important to give open slopes some time before traveling across larger avalanche paths which can fail naturally will winds continue to load the slopes above you. Avalanches will be larger and more consequential in the southern part of the Olympic mountains due to higher precipitation amounts over the duration of the storm. Many of these areas did not see any break in the action on Thursday.

Hurricane Ridge picked up 5-6" of snow Wednesday afternoon and evening before snow changed to a rain/snow mix up to around 5500 ft. This crust may take time to refreeze even as temperatures cool because new snowfall should help insulate it.

ONP rangers on 1/6 dug a snow pit at 4700 ft on a S aspect found 4" of moist snow with 6" of dry snow below that. There was a supportable melt-freeze crust buried January 2nd with around 20 inches of right-side-up lower density snow below that and sitting on another supportable melt-freeze crust.

Keep your guard up and your ambitions conservative given the scale of avalanche activity we've seen with this storm system across the region.

2021-22 Forecast Schedule: Avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week when the Hurricane Ridge road is closed, forecast information will be updated daily to include expected conditions and relevant travel advice under the No Rating label.

Regioni coperte