Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 12 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised.

 

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    3

    Generally stable snowpack conditions exist throughout the forecast area. If an avalanche were to occur today, it would be an isolated persistent slab avalanche. This is a very low likelihood, high consequence scenario. A difficult to trigger weak layer of basal facets lingers above 9,000'-9,500' on NW-N-NE aspects. The most likely points for human triggering exist at relative shallow areas of the snowpack commonly found near exposed rocks, isolated trees, and along cliff bands. While triggering a large avalanche is not outside the realm of possibility today, it has become more of a future snowpack concern following additional new snow loading.

Avalanche Discussion

Observations made yesterday near 10,000' on Relay Peak (Mount Rose area) indicated that basal facets remain on upper elevation N aspects. Snowpit tests indicated that transferring sufficient force through the mid and upper snowpack to collapse these weak facets is very difficult to accomplish. This is a major contributing factor as to why avalanche activity is not occurring in areas where this weak layer exists. Snowpit tests further indicate the once collapsed, fractures readily propagate over distances along the top of this weak layer. This has potential implications under future new snow loading conditions that can stress the snowpack much more than a typical human trigger.

Observations were also received from the South Ridge of Red Lake Peak (Carson Pass area) from a NE aspect at 9,000'. In this area basal facets were absent and no signs of instability were noted. Based on the submitted snowpit data, this appears to be a location where new snow from the last storm cycle fell on bare ground.

Régions couvertes