Avalanche forecast

Olympics

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Winds will drift incoming higher-density snowfall into drifts, loading start zones near ridgelines. Colder temperatures and stronger winds at upper elevations will enable more rapid slab growth. Steer around steep slopes under fresh, sharp cornices where winds are actively accumulating snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Fresh wind slabs will grow as light snowfall and ridgeline winds increase. The day may start out with low hazard at middle elevations, but once snow starts accumulating and moving, slabs will grow on lee slopes. How much hazard exists depends on the amount of snowfall and the strength of the winds. The degree of snow transport and cornice growth will help you gauge the developing hazard. Use small wind-loaded test slopes to evaluate these slabs. Steer around steep actively wind-loadings slopes where you suspect deposits may be 6" or thicker. At middle elevations, small avalanches could be most hazardous near ridgelines where they could rake you through trees or over a cliff. At upper elevations, the hazard might be more consequential and could take you for a more significant ride.

    Example: Scoured slopes and sculpted snow show evidence of wind transported snow with actively blowing snow on the lee slope.

    Photo: Sam Luthy

Avalanche Discussion

ONP Rangers had a look around on Thursday and found a skiff of snow over crusts on sun-affected aspects, but highly variable conditions on shaded slopes. Several inches of fresh snow buried a breakable temperature crust on 1/19. In some areas that crust appears as a pair with a wind deposit in between. The recent snow produced wind deposits at most 6-8" deep on NE slopes. There is some cold surface snow, but it is primarily within wind deposits on NE-facing slopes. Most of these slabs were stubborn to unreactive. Cornices are blocky and trimmed back with a little bit of a fin coming off the top from the last round of wind.  Travel conditions were not great, but manageable terrible. 

Several inches of additional dense snowfall could improve riding conditions, but will also increase the hazard on Friday. 

We removed the January Drought Layer (JDL) and associated crust complex as a problem, following a lack of reactive snowpack test results nor avalanche activity last weekend. Facets are sandwiched between a series of crusts (1/10 and 1/29) 16-20" below the snow surface on shaded aspects. 

We do consider this to be a potential layer of concern for wet slab activity as a significant atmospheric river bears down on the region this weekend. Avalanche conditions are likely to deteriorate rapidly on Saturday at all elevations as the rain/snow line rises to 6500 ft, strong winds transport significant snow at higher elevations, and precipitation rates increase throughout the day. Make sure you consult the weather and avalanche conditions and ideally refrain from any overnight outings involving avalanche terrain this weekend.

Share your observations with the community and NWAC. Even if you didn't see an avalanche or a snowpack test, your information is incredibly valuable.  Every afternoon, 4-5 NWAC forecasters from around the region meet to discuss the latest snowpack and avalanche observations, and weather forecast to create the next day's avalanche forecast.  We look at information from the public, other snow professionals, and weather station data to round out our picture.  Share early and often!

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