Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Expect calmer conditions and minimal snowfall compared to the past few days. Layers of snow from the last storm could still need time to gain strength, especially on wind loaded slopes. Reduce uncertainty by choosing lower angle, more planar terrain. Keep an eye out for signs of wet avalanche activity with mild temperatures and also the chance of seeing some sun.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    Friday should bring an end to meaningful snowfall and winds are forecast to be mostly calm. No fresh layers of new or wind drifted snow should develop, but there is still 1-2’ of new snow in some areas. At upper elevations, thicker and drier layers of new snow could need more time to bond and gain strength.

    Assess new snow for instability before moving into bigger terrain. Track new snow depth and distribution as you gain elevation and change aspects. Look for clues like scoured snow surfaces, cornices, and drifts to show you the wind loading pattern in the terrain around you. Use simple tests to look for strong over weak layers and assess stability before committing to steep slopes.

    (2/8/2023)

    Steep and unsupported terrain like this slope is where you would be more likely to trigger an avalanche on Friday.

    Photo: Adam Ü

Avalanche Discussion

Be ready to assess wet snow instability on Friday. Temperatures will again hover in the low to mid-30s and some areas may even see some sun. Avoid travel on or immediately below steep slopes where you see fresh rollerballs, new avalanches, or simply find wet, mushy snow. 

New snow amounts could vary widely across the West Central forecast zone. The White Chuck Tripod added nearly 2' of new snow since Christmas Eve. Other weather stations around the zone recorded 1-2" of precipitation in the last 24 hours. The real question is how much accumulated as snow in different areas when factoring in variations in temperatures and snow level. West Central usually experiences a wide variety of conditions and also a lack of observations. It’s worth looking at the avalanche forecast for whatever zone is adjacent to where you are heading in the mountains.

High danger played out differently in the zones surrounding West Central.  Observers from both Stevens and Snoqualmie Pass reported easily triggering avalanches up to D2 in size with ski cuts and avalanche control work. Warming, continued snowfall, and a transition to rain at lower elevations made for a very upside-down snowpack with dense layers not bonding well to softer and drier snow below.

West North saw much tamer conditions. An NWAC Forecaster found new and wind drifted layers settling quickly and bonding well. No natural or human-triggered avalanches and few signs of instability were observed. They did find large amounts of wind redistribution from earlier in the storm, with anywhere from 6 inches to 3 feet of snow over the crust buried on Dec 21st. 

 

Régions couvertes