Bulletin d’avalanche

Olympics

Northwest Avalanche Center
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Danger d’avalanche

Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Strong winds and a few inches of snow will form new slabs on the lee sides of ridges and exposed features. Watch for blowing snow and fresh cornices to help identity which steep slopes you want to avoid. In some areas, wind drifted snow several feet thick could produce larger and more dangerous avalanches.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    A few inches of new snow and strong southerly winds will form new drifts on top of older slabs in the Olympics Sunday. A snowboarder triggered wind slab on Friday (3/12) demonstrates the potential for travelers to cause avalanches especially in complex terrain. Look for visual clues such as blowing snow, drifts behind rocks, and textures snow surfaces to help you identify which aspects you want to avoid. Given the strong and sustained nature of the southerly winds, you’re most likely to encounter wind slabs on W-N-E aspects. Steer around suspected wind-loaded features at mid and upper elevations and seek out lower angled or less wind-affected terrain. While some of these potential avalanches may remain shallow and only involve the new snow, others could fail several feet deep, break widely, and become large.

    (3/12/2021) A snowboarder triggered a large avalanche in Klahhane Bowl on a N aspect around 6000' (run locally know as Holy Roller). The slide was triggered from the ridgeline and the rider was not caught. This large avalanche ran 1300' vertical feet covering skin tracks from earlier in the day. The crown was estimated at 2-4 feet deep. SS-ASu-D2+.

Avalanche Discussion

The Olympics should see showers and strong winds during the day on Sunday. Initially, some of the precipitation may fall as rain. Cooling temperatures will transition the rain to snow quickly for mid and upper elevations. Some locations around the zone could receive 3-6” of snow before the afternoon. The new snow and strong winds should slightly increase the avalanche danger throughout the day. Near the rain-snow line, you may encounter a few small loose wet avalanches. Given the current snow surface and minimal rain, we expect these slides to remain localized to very steep slopes. At lower elevations, a well-settled snow surface should limit the avalanche danger. 

On Friday a snowboarder triggered a large wind slab avalanche above Klahhane Bowl on a run locally known as Holy Roller. The slide broke 2-4’ deep and ran 1300’ covering tracks from earlier during the day. Fortunately, no one was caught. (See media gallery below for more details.) 

The aspect of the slope will largely dictate the snow you encounter. On more northerly aspects, 1-2’ of cold dry settled snow overlays a recent crust from 3/6. In terrain that receives more direct sunshine, the surface snow underwent several melt-freeze cycles this past week. Despite recent temperatures, below the surface, the snowpack remains very winter-like. You can still identify many of the storms, crusts, and interfaces from the past month. This includes the mid-January layer. Observations on Friday found this persistent layer 5-6’ below the surface. While the Olympics haven’t seen an avalanche on this weak layer in some time, keep this layer on your radar if you travel to more remote areas and as we head further into the spring. 

Give the changes in the snow surface by aspect, elevation, and overnight freeze, anticipate variable travel conditions Sunday. You could encounter fresh powder, wet heavy snow, breakable crust, or firms slopes. 

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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