Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 4 years ago.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

Highlights

Merry Christmas! Along with jingling bells, you could find challenging travel conditions. Warming temperatures will slowly saturate the snowpack and could make for wet loose avalanches on Sunday. Steer around steep slopes if you observe avalanches that entrain wet snow.

Avalanche problems

  • Loose Wet

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

    Heavy 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. I wouldn't' be surprised to see some natural activity as well. 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, or breakable 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. 

    Example wet loose avalanche with some dirt in the debris.

    Photo: ONP Rangers

Avalanche Discussion

WSDOT did a round of control work on Saturday and reported a number of avalanches, one of which crossed Hwy 2. The storm was a complex battle between warm, wet air and very cold air. The weather stations don't tell the fully story either, as most precipitation buckets are clogged with sleet. You could expect wet snow at upper elevations, a stout ice crust somewhere in the middle, and sleet over dry snow at lower elevations. Temperatures continue to warm on Sunday, so most likely you'll find wet snow in most places. 

On the 18-20th, Stevens Pass picked up cold, dry snow with 3-day 24-hour totals reaching nearly 3 feet. The December 18th interface holds weak grains of small facets, surface hoar, and crusts on southerly aspects. Josh found easy, sudden shears in snowpack tests on this interface last week. You may also find a layer of surface hoar from December 8. Near the base, weaker snow buried in late November, can be found around a couple of crumbly crusts. While they haven't been involved in avalanches in over a month, a very big storm could activate them.

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