Avalanche forecast

Olympics

Northwest Avalanche Center
View on map

Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map
Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You can trigger a dangerous and large slab avalanche on any slope steeper than 35 degrees, near or above treeline. Wind-loaded slopes where you find punchy snow or lens-shaped pillows are most hazardous, but unconsolidated snow in wind-sheltered areas can also produce a large avalanche in wind-sheltered areas. Below treeline, when rain falls on more than 6" of dry snow, expect small point release avalanches and retreat to low-angle slopes.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    We're expecting moderate winds and snowfall (5-8") to ramp up on Friday, creating increasingly dangerous wind slabs as the day wears on.  Moderate to strong winds will rapidly redistribute the snow that falls, piling it onto lee slopes, cross-loading mid-slope features, and scouring slopes others. Fresh wind slabs are overlying wind slabs that formed Wednesday and Wednesday night, which may continue to be reactive. To make matters worse, if you do find wind-sheltered terrain, 12-13" storm slabs showed notable propagation on Thursday. Fresh and dense snowfall will likely worsen the problem as the reactive layer struggles to support the new load. Cracking as you travel, settlement, and difficult trail-breaking, are all signs that there are dangerous avalanche problems in your terrain. Stick to slopes less than 35 degrees near and above treeline and travel along ridgelines to avoid wind-loaded slopes nearby.

    (12/17/2020) These wind slabs formed Wednesday and fresh wind slabs will form anew on Friday.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    You may find storm snow above a crust when you start the day, but as snow levels rise and precipitation intensifies, snow may change to rain at lower elevations. Rain will destabilize the upper snowpack and if it penetrates deeply enough, it could entrain snow all the way down to the 12/10 crust to produce a large avalanche. If you find yourself in snow you can sink into deeper than your ankle, stick to lower-angle slopes. These avalanches are most problematic where they push you into a terrain trap or over a cliff. The Wet Loose avalanche problem should be limited to a small zone in the upper portions of the treeline band where there is enough coverage and at least 6" of previously dry snow above the 12/10 crust. At lower elevations, the terrain is still rough and snowpack shallow. 

    Example: Wet loose avalanches.

Avalanche Discussion

Hurricane Ridge picked up 18 " of new at Maggie's storm board since last sundy. The area is just beginning to add snow to previously partially exposed southerly slopes, which now have approximately 8" above the 12/10 crust. Northerly slopes added 25-28" in wind-loaded areas. The snow came in several storms and a cooler system arriving Tuesday produced slightly weaker (less dense) snow down 16 inches that professionals found exhibited significant reactivity in slopes tests. Slightly weaker snow above the 12/10 crust yielded inconsistent results in snowpack tests, but is not believed to be a concern without significant additional loading of snow or rain. There are no layers of concern below the stout 12/10 crust.

 Travel conditions in many lower elevation areas have become challenging following a warm and wet first half of December.  Travel cautiously, particularly in forested areas where numerous obstacles lie just beneath the surface.

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.

Regions covered