Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Your risk of avalanches lies within the snow above a refreezing crust. You can trigger a potentially large slab in a wind-loaded start zone and a sizeable ride on a steep or unsupported open slope. Ease into the terrain, knowing that reactivity should peak early in the day.

Problemi valanghivi

  • Storm Slabs

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

    Storm slabs could take you for a ride in sheltered terrain and will be large in wind-drifted start zones. Around a foot of new snow will be most reactive as it continues to blow and snow, early in the day.  As you ascend, use test slopes and your favorite quick tests to check particularly for mid-storm instabilities. Note any upside-down character as you enter wind-affected terrain.  These slabs will be larger, easier to trigger, and more widely propagating in wind-loaded start zones in cross-loaded gullies. Avoid the aforementioned features along with open slopes greater than 35 degrees. Poorly supported rollovers in the terrain should be treated with particular suspicion.

    Example: Propagation of the slab out from your floatation device.

    Photo: Sam Siemens-Luthy

Avalanche Discussion

Hurricane Ridge picked up 1-2" inches of wet snow Saturday along with very small amounts of blowing snow. This follows around 1" of rainfall Friday night that wetted the 8" of cold, dry snow that previously existed on shaded middle elevation slopes. It seems like the snowpack absorbed the water well and generally was not prone to wet avalanche activity on Saturday, but visibility was poor.

We're expecting drastic changes once again going into Sunday. When all is said and done, there should be about a foot of snow above the refreezing crust. This snow should have a generally right-side-up profile, but mid-storm instabilities are likely to form within intense banded showers. Despite the widespread nature of the storm slab problem, wind loading should be on your mind as you approach the terrain as it will exacerbate the risk of an impactful avalanche.

The active pattern comes on the heels of a week of high pressure, which allowed the snowpack to gradually consolidate. Prior to the current storm, the Hurricane Ridge snowpack was generally around 2 ft deep, with 35" or so on N-facing aspects.  It consolidated 3-4" with the rainfall on Saturday.

There was an isolated small glide avalanche on a grassy road cut (image in the gallery). This activity should be waning, but be aware that glide cracks from the rain event may lurk.

The eastern Olympics may or may not have seen enough to rainfall to wet the upper snowpack. If you travel in a snowpack without a supportable recent crust, you should travel more conservatively and take this observation from Friday into consideration.

Early season hazards remain in the terrain and shallow snowpacks generally limit real avalanche hazard below around 4400 ft. South-facing exposures have lost significant coverage during the warm-up. Be aware of potentially shallow coverage throughout the terrain as new snow covers potential obstacles.

2024-2025 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 until the end of March.  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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