Avalanche forecast

Olympics

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Wind slabs will retain more reactivity on colder shaded aspects, while direct sun will destabilize other aspects to produce wet loose avalanches. Human-triggered wind slabs exhibited a poor bond to underlying crusts on Saturday, indicating the potential for similar avalanches on Sunday. Move away from sun-affected slopes if you find wet or sticky snow.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Despite the cool weather, we think that the sun will win the battle producing loose avalanches that entrain the 5-6" dry snow that remains on most aspects.  Slopes receiving sunshine will destabilize rapidly, potentially producing dry loose avalanches and then wet loose avalanches as the snow surface becomes sticky and wet. These avalanches start snow shedding off trees or rocks, but gain momentum on long steep slopes. Move from sunny to shaded aspects and reduce your exposure to steep slopes above. Extreme terrain or terrain traps such as gullies or cliffs will increase your risk of injury from any avalanche.

    Example: (3/27/2021) A natural wet loose avalanche (D1.5) on a sun-exposed slope in the Mt. Baker Backcountry. Photo: Zack McGill

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Three wind slabs with 6-12" crowns released at Hurricane Ridge on Saturday confirm that wind slabs lurk in the terrain and that humans can trigger them. The public observation also indicates poor bonding between the new snow and the underlying crust that may take several days to heal. As a result, we expect wind slabs to retain reactivity on Sunday. Shallow wind slabs formed on Saturday towards the onset of the recent storm. These slabs will be covered by less wind-affected snow, making them more difficult to identify. Use your pole to check for firm or punchy layers several inches below the surface. Slabs may run efficiently on either the 4/9 or possibly the 4/7 crust.  Be aware that sunshine can rapidly alter snowpack properties, potentially consolidating slabs and increasing the risk of human-triggered avalanches. Steer around wind-loaded slopes, particularly below freshly corniced ridgelines. 

    Example: (3/29/2021) A fresh cornice on SE, 5,650ft in Highlands Bowl at Stevens Pass highlights the potential for wind slabs on the slopes to the lee (right) of the feature.

Avalanche Discussion

Several storms in the past week have dropped significant snow in the Hurricane Ridge area. The Friday-Saturday storm dropped 5.5" of snow. Depending on the aspect, the fresh snow should sit on either an old snow interface or breakable melt-freeze crust (4/9) formed during sunny weather on Thursday.  Below that crust, around 5-8" of dry snow should be consolidating above another crust (4/7) that exists on nearly all aspects and elevations. Each April storm forms well-defined layers, particularly crusts. We'll need to watch these crusts carefully once warmer weather returns, concentrating meltwater in specific layers.

Although the Hurricane Ridge area experienced a quiet week without significant reported avalanche activity, that has not been the case throughout the region. 

On Friday, multiple riders triggered avalanches, including an involvement where a skier was caught and carried. In one such occurrence,  the crown was 2 ft deep and the slide ran 600 vertical feet. This caps a week that saw multiple avalanche involvements and near-misses around the Cascades, including in the West South where a snowboarder was caught and carried by a large avalanche on Mount St. Helens. We continue to bring up that the snowpack has not made its full transition to a springtime snowpack, and this past week provides proof of that with both dry and wet avalanches driving these involvements. As we navigate our way through springtime weather, the transitions between dry and wet avalanche problems can be rapid and unpredictable, just like the weather. It can make decision-making and forecasting challenging since you can’t bring your winter mindset or spring mindset to the mountains to rely on for any given day. Perhaps the best advice is to learn from these recent incidents and dial back your terrain choices until more stable weather and snowpack patterns prevail.

The snowpack in the Olympics is in great shape for early April with significant depth and excellent coverage.  

Are you out in the Olympics?  Let us and the backcountry community know what you see and Submit an Observation. 

Spring Forecast Schedule:  NWAC will issue a danger rating every day for the Olympics beginning Friday, April 2nd  - Sunday, April 18th. 

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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