Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A tricky and complicated snowpack to compliment the tricky and complicated weather. Ring those sleigh bells, but travel could be challenging with breakable ice crust in some areas. Wet loose avalanches are the problem to look out for as temperatures from the north pole begin to thaw. 

Avalanche problems

  • Loose Wet

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

    Heavy snow, sleet and freezing rain fell on Saturday. The snowpack beneath is still largely dry and weak. As it undergoes a transition to wet snow, you may be able to trigger wet slides that entrain deeper snow and become large. Widely propagating wet slabs could also be possible. Recently buried layers of small facets and surface hoar could act as the weak layer for wet slab avalanches. In other areas you might just find challenging or slippery travel with a stout freezing rain crust. The current conditions are a bit unusual, and wet slides themselves can be hard to predict, so give yourself an extra margin of safety with your travels. 

    Look for recent avalanche activity as the number one bullseye of instability information. Wet, sticky snow that creates rollerballs are a good indicator that wet loose avalanches could be possible. 

     

    If roofs begin to release snow, use extra caution around the exterior of buildings. Roof avalanches can be fatal. 

    Example large wet loose avalanche Photo: Matt Primomo

  • Persistent Slabs

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

    Persistent slab avalanches can propagate widely, and you could trigger them from lower angle slopes adjacent to steep terrain. One obvious clue is loud whumping collapses, this signals that the snowpack can produce an avalanche. This is a complicated snowpack with many weak layers, and it is transitioning from cold and dry to a warmer and wetter regime. With a wide range of variability in the zone, slides could take on the nature of wet slabs, or they could be dry. Hedge your bets and give the snowpack time to transition before trusting steeper, open slopes. 

    There are numerous potential persisting weak layers to consider. Last week, touchy avalanche conditions were observed, with collapses and avalanches failing on weak snow on the 12/18 and 12/8 interfaces. These were down about 18" beneath the snow surface and on all aspects. In areas with a snowpack of less than about 3ft, large, weak faceted crystals from mid-Novemeber 11/22) are still lurking near the ground. 

    (12/21/2022)

    Intentionally skier triggered slide on Wednesday in Icicle Creek that failed on weak faceted snow at the 12/18 interface. 

    Photo: Nate Hough-Snee

Avalanche Discussion

The areas near the crest picked up substantially more precipitation amounts than the Wenatchee mountains, so expect residual danger to be greater near the crest. Water amounts near the crest are: 1" at Sasse Ridge and 1.5" at Trinity, however these are wildly different places at the moment. Sasse is likely a thick freezing rain crust, while Trinity has 6" of heavy, dense new snow. Many NWAC weather stations aren't registering precipitation as they are clogged with sleet. The snowpack has only begun to transition to wet snow near the surface. It'll take time for it to adjust, and in doing so we could so sporadic natural avalanches. Keep your wits about you if you do go out into the mountains, it's likely to be a dangerous place on Christmas. 

Regions covered