Avalanche forecast

West Slopes Central

Northwest Avalanche Center
View on map

Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

New snow and wind will build fresh slabs in leeward terrain near and above treeline. Use visual clues to identify and avoid wind-loaded slopes greater than 35 degrees. Keep cornice fall and glide cracks in mind, and continue to steer around slopes where these hard-to-predict hazards exist.

Avalanche problems

  • Wind Slabs

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

    After a slow start to the storm during the day Thursday, temperatures will drop with increasing winds and snowfall overnight. Fresh slabs of wind drifted snow will form on a variety of old snow surfaces and could be reactive to the weight of a person at upper elevations. Approach leeward terrain above 4000ft cautiously, especially near ridge crests and convex rollovers 35 degrees and steeper. Look and feel for sudden changes in snow surface texture and hardness as you transition into wind-affected terrain. Recent avalanches, cracking, or collapsing should direct you to simple, lower angled terrain. Be ready to make your own assessments if you venture into upper elevations. If new snow hits or exceeds the high end of forecast amounts (8-10in), expect the danger to reach CONSIDERABLE above treeline and dial back your travel plans and terrain selection.

    (3/8/2021) Example photo of a small natural wind slab on Wright Mountain in the Snoqualmie Pass Zone. The slab broke near the base of cliffs and the cornice above serves as an indicator of the wind-loaded slope below. [Photo: Trevor Kostanich]

Avalanche Discussion

The storm will ramp up Thursday evening and periods of snow will continue through the weekend. New snow and wind will drive avalanche concerns at upper elevations, while the hazard will remain limited below treeline. In addition to slabs of wind drifted snow, keep cornices in mind as these already large features will continue to grow the next few days. They could drop onto slopes below acting as huge triggers. Stand back from cornices along ridgelines and minimize overhead exposure to these features. Several large glide cracks and a few glide avalanches were observed recently as well. These avalanches are difficult to predict, but if you notice crevasse-like cracks in the snowpack, avoid these slopes and areas below. 

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.

Regions covered