Bollettino valanghe

Olympics

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

Small avalanches may run farther than you expect on a firm crust. Wet or dry avalanches may be easy to trigger and could also release naturally on sun-exposed slopes. Limit your risk by considering the consequence of the terrain around you, including exposure above terrain traps and cliffy terrain.

Problemi valanghivi

  • Loose Wet

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

    Wet avalanches may be easy to trigger and could run far on the crust, gaining momentum and enough mass, on slopes 35 degrees and steeper, to cause a problem in higher consequence terrain. Sun warming recent snow will be the primary driver of instability, making it easier for you to push wet snow or for snow falling off rocks or cliffs to naturally trigger an avalanche. Notice the terrain around you and limit your exposure to the types of cliffs, creeks, and extreme terrain features that could get you into trouble if an avalanche were to knock you off your feet and take you for a ride. 

  • Storm Slabs

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

    There will be enough dry snow at upper elevations to warrant a storm slab. We're expecting around 4-6" of storm total relatively dense snow that may release as a heavy slab that entrains as it moves. These could exist on any aspect, but will have a different character depending upon how much the sun warms the snow in your area. Use simple slope tests to evaluate the snow above the firm 3/23 interface at the base of the storm snow. This bond should be improving, but slabs change their character quickly in the springtime, so expect rapid changes as the day progresses and you move to different aspects. As with the wet snow problem, limit your exposure to high-consequence terrain to manage the problem. If you find upper-elevation terrain with more than 6" of snow, wind drifting may accentuate the problem near ridgelines. 

    (3/13/2024)

    Example: Upslope track test reveals a shallow storm slab.

    Photo: Robert Hahn

Avalanche Discussion

It feels like spring at Hurricane Ridge with a mix of wet and dry snow avalanche problems. We've come out of a prolonged warm spell that reduced the Hurricane Ridge snowpack from its season maxima of 80" on March 12 to 52" on March 23rd. Temperatures have flucturated around the freezing mark the last several days. A band of moderate snowfall early Saturday brought a quick 3-4" of snow above the 4000 ft snow level. After a break in the action during the day, rain and snow returned with temperatures at 33F at the Ridge, before dropping. This band of snow could bring another 1-3" of snow through the evening hours, bringing settled storm totals to around 4-6" above the 5000-5500 rain/snow line peak on Saturday. This bit of rain may create a shallow punch crust on middle elevation slopes on Sunday, but we don't expect it will exist at upper elevations.

NWAC Observers and Park rangers traveled to around 6000 ft on the west side of Mt Angeles on Thursday and conditions were similar with some very light rainfall on Friday. Most aspects are losing their winter layering rapidly. On southerly aspects, even the crusts are no longer apparent. On northerly aspects, a highly variable crust up to about 8" thick overlies a relatively homogeneous snowpack to the ground. On these aspects, there were several crusts, but none yielded notable results. The snowpack in this area has handled a fairly rapid transition to spring quite gracefully. There had been some minor wet loose activity over the last week, but they didn't observe signs of glide cracks forming. You can read their full report here.

An observation from the Mt Olympics area shows very large D2.5-D3 avalanches that entrained down to the ground on some very steep sun-exposed aspects. These types of avalanches are highly unlikely with somewhat cooler temperatures moving forward. However, if you're in areas with smooth, bedrock slopes with water flowing under the snowpack, a large glide avalanche is not out of the question. Consider the terrain you're hanging out under if you travel in deeper snowpack parts of the Olympics.

2023-2024 Forecast Schedule

NWAC will issue an avalanche forecast every Friday, Saturday, and Sunday and every holiday mid-week day the Hurricane Ridge Road is open from December to early April.  We will issue Avalanche Watches or Warnings when conditions warrant.  We will not update the non-holiday midweek discussion.  Our mountain weather forecasts will continue to cover the Olympics and are issued twice a day through the end of April.  If you have questions or feedback, please contact us at [email protected] and [email protected]. 

If you're out in the snow, share your observations with us and your local backcountry community.

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