Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

If the snow surface is changing throughout the day due to the sun’s input and warm temperatures, take note of what hazard the terrain above you contains and adjust your travel plans accordingly. If you are staying out of the sunshine, look for wind-drifted piles of dry snow to steer around as you ascend in elevation.

Problemi valanghivi

  • Loose Wet

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

    Keep an eye out for rollerballs and pinwheels or the snow surface getting warm and sticky as indicators that the sun is destabilizing the snow surface on Friday. If you notice these signs, natural Wet Loose avalanches may follow or you may be capable of pushing snow downhill to create Wet Loose avalanches of your own. These avalanches will be more likely on slopes that see direct sunshine, particularly later in the day as the snow surface softens, and could be larger as you ascend in elevation. These slides often start at a point and can entrain snow, fan-out, and even trigger slabs as they descend downhill. You can minimize your exposure to these avalanches by heading toward shadier slopes and ensuring that the slopes above you are not in the sunshine.

    (2/28/2021) With rising freezing levels and sunshine in the forecast, look for rollerballs and pinwheels as indicators that Wet Loose avalanches may be possible. This photo is from our last warmup about a week and a half ago. [Photo: Ashley Turcott]

  • Wind Slabs

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

    This past week’s storm track certainly produced for the Olympic Mountains. Although we are a few days removed from the storm, don’t be surprised to find some lingering storm instabilities, particularly in areas where the wind was able to drift the snow into deeper piles. You could be more likely to encounter these slabs as you ascend in elevation or near rocky features such as cliffs and gullies. You can look for freshly built cornices, textured snow surfaces, or smooth pillow-like piles of snow to help you identify wind-loaded features that you should steer around.

    (3/4/2021) This past week was very stormy in the Olympic mountains with multiple feet of new snow and strong winds depositing snow into Wind Slabs and building out cornices. [Photo: NPS Rangers]

Avalanche Discussion

Freezing levels on Friday are expected to continue to rise as high pressure and mostly sunny skies maintain their hold on the Olympic Mountains. Small Wet Loose avalanches and rollerballs were observed at Hurricane Ridge on Thursday on slopes that receive direct sunshine, and we expect this to continue into the start of the weekend. These avalanches have needed some time to overcome the cool morning temperatures, meaning that hazard is typically increasing throughout the day as the sun’s influence grows stronger. This same phenomenon could also destabilize cornices, which have grown large recently around Hurricane Ridge. Cornices notoriously break further back than expected and often fail during periods of warmer weather. Give these beasts a wide berth as we transition toward a more spring-like snowpack by not traveling under them and staying far back on ridgelines. 

On aspects that do not see direct sunshine, you could find that cold dry snow still exists over the 3/6 crust. Signs point toward the bond to the crust weakening, so keep dry loose avalanches or pockets of wind-drifted snow on your radar on these slopes and don’t get swept off your feet in consequential terrain.

Throughout February, we have been tracking a layer (Mid-January crust/facet combo) deep in the snowpack that was responsible for some very large avalanches throughout the Cascades. This layer was active in the Olympics in early February, but we haven't heard from it in multiple weeks and are considering it dormant for the time being. Observations on Thursday indicated that this layer is between 5 and 6 feet down at Hurricane Ridge and we will be sure to update the forecast with more relevant information in the future if we believe this layer is waking up again. 

2020-21 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.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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