Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

Light rain, balmy conditions, and melting will maintain the risk of wet avalanches.  Danger will persist until the mountains see a long period of colder temperatures. Avoid traveling under cornices, cliffs holding unstable-looking snow features, and glide cracks to reduce the chance of being overwhelmed by an avalanche.

Avalanche problems

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Multiple glide avalanches and cornice failures were noted around the Baker Backcountry on Sunday. [Glide avalanches occur when the entire snowpack is lubricated by water and slides on a smooth ground surface like a rock slab]. A week of warm weather and rain is taking its toll and the mountains are slowly coming unglued. It’s safe to assume this pattern of avalanche activity will continue across the North and Central Cascades until we see a solid refreeze. No new natural wet loose were observed but they should still be considered a hazard in steep terrain.

    The only way to reduce risk is to avoid being directly under very steep slopes, cornices, glide cracks, and steep, rocky areas still holding snow, especially during rainfall or periods of sun. The same advice holds true when the snow surface is wet and unsupportable. Avalanche activity is less likely when a thick, melt-freeze crust is present at the snow surface.

    Though most avalanches in the last week were “naturals” it’s still possible for a person to trigger a wet loose in very steep terrain holding saturated, unconsolidated snow - which is pretty much everywhere. Cornices could also fail under the weight of a person or snowmobile. 

    (3/27/2022)

    Cornice failure and glide avalanche on Huntoon Point on a northeast aspect at 5100'.

     

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3

    With improved visibility also came a few more reports of deep slab avalanches from across the North Cascades. They are suspected of releasing in a layer of weak, faceted snow buried on March 8th. Some appeared to be triggered by a falling cornice from above. All were naturally triggered. The likelihood is low that a single person could trigger one of these dangerous avalanches as the layer in question is buried 4-6’ deep or deeper. The greater concern is that one releases in alpine terrain above you triggered by a big load like cornice fall or a smaller wet snow avalanche. Though all known avalanches of this type initiated near or above 5500', some traveled far down into treeline. 

    As with the wet avalanche concerns listed above, there isn’t really much you can do to outmaneuver this problem. You are either in the terrain where one of these avalanches might occur, or you are not. If you choose to travel in these areas your a simply accepting a slightly higher likelihood of getting hit from above. Traveling in the morning or other times temperatures are cooler will lessen risk but is no guarantee . . . 

    (3/27/2022)

    D3 avalanche suspected of releasing in the March 8th faceted layer. This avalanche was witnessed on the morning of March 23rd.

     

Avalanche Discussion

Look for freshly wind loaded features and shallow slabs anywhere it is cold enough for dry snow to accumulate. Track the depth of new snow as you gain elevation or change aspects. Evaluate the bond of new snow layers before getting into steep terrain with consequences.

The upper snowpack is weak and wet with rain and melt-water having penetrated the upper 100cm.  Sunday night will be the third in a row without a decent freeze - slightly lower freezing levels on Monday will do little firm things up. Skis or other floatation will keep you near the surface, but you will sink shin to knee deep if you get out of your gear. 

Though the bulk of natural wet loose avalanche activity has run its course, overhead hazard with the “spring shed” continues. Plenty of avalanche terrain presents low risk, but it can be difficult to predict which slopes will or won’t produce avalanches or other hazards until the mountains get a good freeze and stop slowly falling apart. 

Avalanche, snowpack, and weather conditions vary quite a bit between zones to the north, east, and south of West Central.  Greater quantities of new snow to the north have made for an extended period of wet avalanche activity given the current mild temperatures. In addition, large avalanches releasing in a faceted layer have occurred to the north while Stevens or Snoqualmie Passes have seen no avalanches of this type. With limited observations in West Central refer to forecasts for Stevens or Snoqualmie Passes if traveling in terrain adjacent to those zones

 

 

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