Bulletin d’avalanche

Eastside Region

Eastern Sierra Avalanche Center
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Danger d’avalanche

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

Points saillants

Moderate amounts of new snow and strong winds have likely created fresh and sensitive wind slabs in leeward catchment zones at all elevations and may have added stress to buried persistent weak layers in the upper snowpack. Large natural and human-triggered avalanches are possible today. Be on the lookout for continued wind transport and use conservative terrain choices to limit your exposure.

Problèmes avalancheux

  • Wind Slabs

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

    Modest snow totals and strong to extreme winds have likely created fresh wind slabs in leeward catchment zones. Be particularly cautious in areas with higher snow totals from last night’s quick-moving storm. This may include higher elevations and areas closer to the crest. It will be crucial to conduct your own localized assessments. While most concerning near and above treeline, extreme winds can redistribute snow in atypical ways. Don't be surprised to find wind-deposited snow in isolated areas below treeline. Blowing snow, recent avalanche activity, large drifts, and recent cornice growth are all clues that can help you identify and avoid areas with recent wind deposits. Be suspect of terrain features that encourage drifting, such as the leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions.

    Large wind slab avalanche.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3

    Persistent weak layers in the upper snowpack continue to show the potential to create large avalanches. While recent snow accumulations are not substantial, fresh wind loads have likely added stress to these layers, and triggering a large avalanche may be easier today in areas where problems overlap. Managing this problem requires extensive evaluation and deliberate terrain choice. Avalanches have been failing without prior warning signs like cracking or collapsing in the snowpack and several recent avalanches have been triggered from a distance. Remember that persistent slab avalanches often propagate across and beyond terrain features that would otherwise confine surface instabilities such as wind or storm slabs. Use conservative terrain choices to limit your exposure.

    (3/31/2023)

    Large remote triggered avalacnhe in V-Bowl, Lee Vining area, 9000' BTL, 3/31/23

Avalanche Discussion

While new snow totals from yesterday’s storm were mostly modest, it will be important not to let our guard down. Localized assessments will be critical if you venture into the backcountry today. Areas that received higher snow totals will be areas with more elevated avalanche concerns. Persistent weak layers in the upper snowpack continue to produce avalanches. Several recent avalanches have propagated widely and failed without warning as skiers, snowboarders, and snow machiners were traveling in nearby terrain.  Giving yourself wide terrain margins remains the best strategy for avoiding large avalanches.

In addition, there are several objective hazards to consider today. Very cold temperatures and strong winds are likely to create dangerous wind chills in exposed areas. It will be worth considering the dangers of exposure and plan accordingly by bringing extra warm layers and equipment to prepare for the elements. Dealing with unforeseen equipment malfunctions or injuries could be a bitterly cold affair.

Régions couvertes