Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 13 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The avalanche danger has dropped to LOW on all snow covered slopes due to a shrinking snowpack. Human triggered avalanches are unlikely today but not impossible. Some persistent slabs may continue to lurk on isolated terrain features. The SE-S-SW-W aspects do not have enough snow cover on them to warrant a danger rating.

Problemi valanghivi

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1

    As the snowpack has become more shallow, the persistent slabs have fragmented and no longer connect across large slopes. This loss of snow has also decreased the weight on top of the persistent weak layers. Additionally, the overlying slab has lost strength and become less of a slab, and the persistent weak layer has had a month to adjust to the load above it. All of these factors combined have made triggering persistent slab avalanches unlikely. Unlikely does not mean impossible. Some unstable persistent slabs may still lurk on isolated terrain features on NW-N-NE aspects. These avalanches would remain small due to the lack of snow; however, getting caught in one of them would result in collisions with rocks, logs, or trees due to that same shallow snowpack.

    Even though the avalanche danger has deceased, the barely covered rocks, logs, trees, stumps, and other obstacles including areas of bare ground on all aspects still make on-the-snow-recreation challenging. All of these things have become difficult to avoid, and collisions with these things could easily injure a person or break equipment. 

Avalanche Discussion

After a month of observations that predominately indicated an unstable snowpack, the last 4 days of observations have shown a trend toward more stable conditions. Yesterday, observations and data did not reveal any signs of continued instability from an area near Red Lake (snowpit, more info) that had consistently yielded obvious unstable results since Dec. 7th. The weak sugary layer of snow in the bottom third of the snowpack still exists, but tests on this layer indicated that triggering a fracture that travels along this layer has become unlikely. This data matches the data collected earlier this week in Deep Creek, on Rubicon Peak, and on Lincoln Ridge.

Overall, finding areas with consistent snow cover has become more and more difficult. With each passing dry day the already anemic snowpack continues to wither away exposing more and more obstacles and areas of exposed ground.

Regioni coperte