Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

While the few inches of new snow may not pose too much of a significant hazard, if the sun comes out, expect a barrage of rollerballs and probably a few small natural avalanches. Keep tabs on the sky; this change won’t take long if the sun pokes through.

Avalanche problems

  • Loose Wet

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

    With relatively mild temperatures, it won’t take long for conditions to warm if the clouds start to break. We’re expecting at least some periods of sunshine throughout the day. Often you’ll first notice snow falling out of the trees or off rocks. These “tree bombs” may initiate piles of rollerballs on slopes below. Wet loose slides are probably close behind. 

    Whether natural or triggered, these smaller slides are easier to manage. However, even tiny avalanches can hurt you if they push you over a cliff or into a creek. So, pay attention to the consequences of the slopes below you. 

    Even in shaded terrain, this new snow comes with some risk. Cooling temperatures and light winds should allow it to fall right-side-up and bond well to the old surface. However, you may still trigger a small slide in the new snow (loose or slab) in very steep areas or wind-affected terrain.

    (3/15/2024)

    Example: Rollerballs and small wet loose slides from steep rocky terrain.

     

    Photo: Andy Harrington

  • Deep Persistent Slabs

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

    A new crust is growing just below the new snow. As it gets thicker and gains strength, it will help reduce any concerns about avalanches failing on older, deeper layers in the snowpack. The cooling trend on Saturday will help significantly!

    These avalanches are becoming very unlikely. They would likely take a bigger trigger (like another avalanche) or finding a shallow spot in the snowpack. 

    Over the past month, numerous avalanches occurred on well-documented layers of facets on and just above the Early February Crust (4-6 ft down). While unlikely, these avalanches would break widely and be very large. Consider limiting any time you spend on or under large complex avalanche terrain, particularly on more northerly aspects, until this crust has time to develop.

    (3/18/2024)

    A widely breaking avalanche in Mount Rainier National Park. It likely occurred on 3/18 and may have broken on persistent weak layers.

    Smaller wet avalanches can be see in the foreground. 

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

A modest storm should bring several inches of snow to the middle and upper elevations around the West South zone Friday night. While a few showers may linger into Saturday morning, things should be drying out and clearing up.

We’re at the tail end of a prolonged warm spell. An extended wet loose avalanche cycle left piles of debris and frozen rollerballs on and under many slopes regardless of aspect and elevation. This period of hot weather took its toll on the snowpack, particularly at lower elevations and southerly aspects. Tree debris now covers the surface in the forest. Patches of bare ground, open creeks, and plenty of obstacles make it feel more like late spring. 

Recent avalanche activity has been minimal and limited to only a few small wet loose slides in the second half of the work week. 

On Friday, an NWAC forecaster at White Pass found a firm crust above 5800ft. It was nearly 10 inches thick and growing. Lower in the terrain, the crust was still present but weaker and more variable.

Regions covered