Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

We will begin a slow transition away from our mild sunny weather on Wednesday.  You're less likely to trigger a wet snow avalanche but a large natural trigger like cornice fall could still unleash a powerful wet slab avalanche that breaks down to deeper layers.  Continue to employ a healthy dose of caution and steer clear of steep terrain where you find wet punchy snow and give terrain below sagging cornices a wide buffer.  

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Wet loose and wet slab avalanches are becoming less still likely as we start to transition away from our prolonged mid-March warm stretch.  Slightly cooler freezing levels and a stiff westerly wind may lower the danger more quickly at upper elevations on Wednesday, or anywhere you find a firm supportable crust. 

    Wet loose avalanches may be sluggish to initiate on lower angled slopes, but don't be fooled and continue to avoid very steep terrain (steeper than 40 deg) where you find wet, punchy snow.  If you step off your skis, board, snowmachine etc, and you're surprised how much you sink in, don't engage with large open slopes nearby and avoid complex terrain like chutes, gullies and slopes above cliff bands.  Meltwater is still moving through the snowpack and notoriously tricky wet slab avalanches are still possible.  While the likelihood of triggering a wet slab avalanche is lower, the consequences of triggering an avalanche down to deeply buried weak layers from Early February are just as deadly. 

    Be aware of overhead hazard and the terrain you're connected to.  A large natural trigger like cornice fall could trigger a large wet slab avalanche on the slope below.  Stay well out from under cornices and give them a wide berth on ridgelines as they often break further back than you expect. 

    (3/16/2024)

    Snowmobilers triggered this avalanche on a southern aspect in the Ahtanum on Saturday, March 16th. It likely failed and ran on the Early February Crust. 

Avalanche Discussion

NWAC Forecaster Katie Warren was out in the Ahtanum/Darland Mt area on Tuesday.   The prolonged period of sun and warm temperatures had done a number on the lower elevation snowpack and steeper southerly slopes.  Wet snow avalanches from the last few days were not as widespread as in other zones and there were tracks on many slopes in the immediate area.  The snowpack on southerly aspects was wet and moist to the ground, but more supportable than other sunny aspects where you could punch through wet snow to your waist.  Northerly aspects held a colder, more layered snowpack and the early February crust was easy to find about 4' down on a N aspect @ 6700'. 

On Saturday, there was a close call where snowmobilers triggered an avalanche in Ahtanum that failed on deeply buried weak layers.  While we haven't seen any new avalanches on this layer, the structure is there.  The potential for large and destructive avalanches will linger during this extended period of warmth as meltwater moves through the snowpack. Before this warm-up, we had a widespread, persistent slab problem. There was a fatality three weeks ago in Ahtanum Meadows area, and in the neighboring East Central, we saw multiple large human-triggered persistent slab releases last week.  

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