Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
Voir sur la carte

Danger d’avalanche

Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
Open full map
Périmé — ce bulletin a expiré 11 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanche danger remains LOW for all elevations and aspects. Small loose wet avalanches remain possible in isolated areas on all aspects. Normal caution is advised.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1

    Snow from the last storm remains transitional from recent storm snow to melt-freeze in many areas. As air temperatures warm today, wet surface snow will again form on all but the most heavily shaded northerly aspects. The majority of instability today is expected to take the form of human triggered roller balls and pinwheels rather than loose wet avalanches. Isolated small loose wet avalanches are not outside the realm of possibility today on all aspects on slopes 37 degrees and steeper. Many areas below 7,500' on SE-S-SW aspects have melted out to bare ground since the last storm.

Avalanche Discussion

Observations made yesterday on Silver Peak (Pole Creek area) revealed decent to good snow cover in the area on N-NE aspects as low as 7,100'. Below this elevation, snow cover quickly became very thin. Near surface facets were observed as developing in this area on N-NE aspects, but are not a problematic weak layer at this time. Snowpit data collected in the start zone of the main NE avalanche path (NE aspect, 8,280') did not reveal any evidence of instability. Old near crust facets below the thin melt-freeze crust at the base of the recent storm snow were noted as rounding and gaining strength. Snow that was cold and unconsolidated on shaded northerly aspects at 7,800' during the morning hours was observed to enter its first melt-phase around noon yesterday. At that time, skier triggered roller balls reached 8 to 12 inches in diameter prior to breaking apart. A thin breakable surface crust is likely to have formed in the area last night. This is due to refreezing of the miniscule amount of free water at the snow surface that allowed for yesterday's pinwheels. Snow cover on the SE-S-SW aspect slopes on the N side of Pole Creek held little to no snow cover below ~7,700'.

Régions couvertes