Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Heightened avalanche danger exists on all aspects above treeline. At upper elevations, recent new snow and shifting wind direction has continued the risk of wind slab development. These slabs could be reactive to ski, and if triggered, fail deep enough to bury a human. Assess steep slopes (>30 degrees) with caution, looking for signs of instability such as active wind loading, shooting cracks, and collapsing under foot. Below and near treeline, rain-on-snow has saturated the upper snowpack.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    This problem will exist above the snow line, primarily on Mount Shasta. Above 9,500 feet, fresh snow has been falling for the past few days with shifting wind between the west and south in moderate-strong speeds. As the day cools and snow level drops, wind transported snow will deposit at lower elevations. Expect to find wind loading on all aspects above treeline. Later in the day, slabs will begin to develop on NW-N-NE-E-SE aspects near treeline, with cross loading on W and S aspects. On a well-connected slope, these slabs could be large (D2), with potential to bury or kill you.

Avalanche Discussion

The forecasted warm-up has reached its peak, and a cooling trend will commence through the day today. Rain-on-snow has been the story for the last 19 hours, reaching up to 9,500 feet. As of 5am this morning, Gray Butte has finally dropped below freezing, suggesting a snow line of 7,000 feet or so. As cooling continues, the observed wet-loose instability will cease and the snowpack will lock up. Below and near treeline, where significant rain fell, expect the soggy snow surfaces to become firm dust-on-crust by tonight. Above treeline, specifically above 9,500 feet, snowfall and moderate-strong wind has likely formed wind slabs on leeward terrain. For today, snow accumulations will range between 3 and 8 inches depending on elevation. 

Yesterday, forecasters explored the South Fork of the Sacramento, including the Cliff Lake and Gumboot areas. The South Fork road (FS26) has deep ruts from 4×4 vehicles for the first 6.8 miles. Precipitation fell in the form of rain across all observed terrain. Deep rain runnels has formed on most slopes, and the recent four to eight inches of snow has become wet. A natural wet-loose avalanche was observed on a steep slope above Cliff Lake, sliding on a firm crust from earlier in the week. 

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