Bollettino valanghe

Olympics

Northwest Avalanche Center
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Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Avalanche hazard builds from scratch Friday as new snow accumulates and begins to drift. Sensitive wind slabs will develop just below ridgelines and in other lee features. Identify and steer around areas of active snow transport and slopes beneath wind lips.

Problemi valanghivi

  • Wind Slabs

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

    We're expecting 2-3" of fresh snowfall around Hurricane Ridge on Friday with winds barely in the transport range. Generally, deposits of 6" or deeper are required for legitimate avalenche concern. Windier upper elevation slopes and the most exposed ridgelines will get to this threshold first and that is where your initial observations should focus. Later in the day, slabs could connect across ridgeline start zones. On W-N-E aspects, slabs will overly a 1/2" layer of faceted snow sitting above a thick 6" crust. It should be easy to identify the depth of the slab above this easy-to-identify bed surface. Monitor slab depth, and once you suspect deposits of 6" or greater may lurk in your terrain, steer around steep slopes below ridgelines, fresh sharp cornices, or in areas of active snow deposition. Note signs of instability including shooting cracks and easy hand shears above the crust. Such observations would confirm our concern that slabs may be easy to trigger.

    Example: Blowing snow and drifts highlight potentially wind loaded areas. 

    Photo: Sam Luthy Siemens

Avalanche Discussion

A pattern shift is arriving in the Olympics conditions will start to change more significantly than we've seen in recent days as snow falls and redistributes. In a winter where fresh snow is hard to come by, we'll take what we can get. 

Hurricane Ridge picked up around 1" of snow on February 7th, which has consolidated into 0.5" of faceted snow with a layer of "droopy" 3-4 mm surface hoar capping it. This weak snow sits above a 6" crust which acts as a "new ground" on all aspects with snow coverage. There were no avalanche concerns on Thursday. 

I'm not sure we can call it "early season coverage" since it's mid February, but coverage has retreated to the point where there isn't enough snow for avalanche hazard at lower elevations and on many sun-exposed aspects in the Hurricane Ridge area. Remember that if there's enough snow to ride a slope, there's enough base to support avalanche activity. The other aspect of the painfully thin coverage is that random holes, and open creeks are common. Travel hazards rival or in some cases may exceed the avalanche risk. Give yourself extra time to manage the numerous obstacles and snow conditions,

Regioni coperte