Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Stay alert to changing conditions throughout the day, a strong winter storm is knocking at our doorstep. Check the slopes for wind drifted snow, strong over weak layering, and be ready to stay off wind-loaded areas if you find signs of instability like shooting cracks. Wind slabs may be small, but you could trigger a larger avalanche at higher elevations. 

Problèmes avalancheux

  • Wind Slabs

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

    You'll find a fair amount of wind-affected snow at higher elevations, and winds are forecast to increase markedly Sunday afternoon. Look for larger slabs at higher elevations and South winds loading northerly aspects. You could trigger wind slabs on the leeward sides of exposed features including ridges and mid-slope features. With lots of recently buried faceted surfaces, slabs could react in surprising ways. Don't get lured out onto a stiff slab, because they could break above you. 

    Look for signs of instability such as recent slab avalanches, and shooting cracks. Steer around steep slopes with stiffer snow, drifted snow, and wind rippled snow. In many areas of the zone you could find weaker snow near the ground. Slides in heavily wind-loaded areas have the potential to step down to these deeper layers, and become much larger avalanches. Use safe travel protocols and consider each slope separately. 

    (12/28/2021)

    Shallow recent wind slab beneath a cornice. The slide appears to have stepped down to a deeper layer. N at 7,200ft on Mt Cashmere.

    Photo: Matt Primomo

Avalanche Discussion

On New Years Eve, observers reported a fair amount of wind textured and drifted snow. A few small, natural wind slabs were spotted in alpine terrain. Katie Warren was out on Dirtyface and found large surface hoar laying flat on the surface. The Solstice crust was down about 2ft, with small facets above and below. Over the last days of 2021, the East Central zone picked up a few inches to over a foot of new snow. Before this last storm, observers had noted weak snow surfaces due to the very cold temperatures. Avalanche danger is expected to increase substantially Sunday night into Monday, as slabs build up over these weaker layers.

The storm snow from December has generally been settling out, although at it's base a weaker structure exists in many areas. An observation from the Icicle Creek drainage on the 28th showed that weaker snow has formed between deeply buried crusts from earlier in December. A very large avalanche was observed off of Mt Mastiff, on the eastern edge of the neighboring Steven’s Pass zone. A thin crust from the Solstice is now buried 20 to 30 inches in western parts of the zone and 8-15 inches in eastern areas. Above 6000ft, this crust may be difficult to discern or might not have formed at all. While triggering a slide on these deeper interfaces appears unlikely, caution is warranted in larger, alpine terrain of the region.

If you get out please post to our observation page, and help contribute to the forecast!

Régions couvertes