Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Very dangerous conditions exist in the mountains. Heavy snow and rain, along with warming temperatures will create natural avalanches during the day. Stay off of, and out from underneath steep slopes where avalanches can start, run, and stop. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Heavy snowfall with warming temperatures will create instabilities in the new snow. Most storm slabs occur during the storm, and it will be storming on Tuesday. Signs of instability are shooting cracks and recent slab avalanches. These may occur even on small, steep features and could be 12" deep below treeline. At higher elevations slabs could be up to 2ft deep during the day tomorrow, and growing rapidly. Tuesday is a good day to plan to avoid avalanche terrain altogether, staying well away from any steep slope. In addition to slabs on the surface, deeper weak layers exist above 5,000ft in areas with a shallow snowpack, such as the Wenatchee Mountains. Any storm slab or loose wet avalanche could step down to these old weak snow layers and create very large avalanches. 

    Example wide storm slab in the sparse trees.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    Wet loose avalanches will become a problem during the day at lower elevations, with snow turning to rain. These are expected to run on steep slopes and could easily be large enough to bury and kill a person. Signs of wet loose instability include rollerballs, wet sticky snow over dry snow, and recent fan shaped avalanches. Avoid going underneath steep slopes, even if it's on a trail through the trees as wet loose slides could run through open forested terrain. 

Avalanche Discussion

With heavy snow turning to rain, avalanche danger should become High in most parts of the zone on Tuesday. The SW part of the zone (Salmon la Sac and Teanaway) will bear the brunt of the storm. Last weekend, there was a Special Avalanche Advisory in place for the Wenatchee Mountains near and east of Highway 97 due to persistent slab avalanche problems. I checked out Blewett Pass on Monday to see how the area was holding up and found the recent slab had settled out, but propagation was still possible on north and east-facing slopes above 5,000ft. The heavy snow and rain on Tuesday and Wednesday may increase the likelihood of avalanches breaking near the ground.

A recap of last weeks avalanche activity:

Saturday- A skier triggered a slab and went for a ride above Marion Lake. Other skiers intentionally triggered a shallow windslab on a north facing slope at 7,200ft above Eightmile Lake.

Friday- A skier triggered a D2 near Naneum Ridge, and Mission Ridge Ski Patrol triggered a small slide with explosives that stepped down to weak snow near the ground. These were on northerly aspects right around 6,000ft.

Wednesday- Natural D3 observed off of Diamond Head near Blewett Pass. Mission Ridge Ski Patrol triggered a couple of wide D3 hard sabs that ran on old snow near the ground with explosives.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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