Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
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Pericolo valanghe

Sun
Alta quota
1 · Debole
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

Today, generally safe avalanche conditions exist across the forecast area. As temperatures rise, watch for unstable snow on sunny slopes, especially in isolated steep terrain, and near rock faces. Pinwheels, roller balls, and knee-deep boot penetration are all signs that the snowpack is beginning to saturate, and stability is decreasing. Upper mountain explorers, keep your eye out for rock and ice fall as cliff bands begin to shed. 

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Calm winds, rising temperatures, and sunny skies will elevate the possibility of wet loose avalanches today. A moderate refreeze overnight will keep this problem from getting too large or widespread. That being said, these avalanches remain a remote possibility from a human trigger late in the day. Though these avalanches are expected to be relatively small, they could be large enough to knock someone off their feet, or carry a person into consequential terrain. As the day progresses, if temperatures continue to climb, instability could rise a touch. This period of time would be relatively short-lived before the evening cool down. Look for early signs of a destabilizing snowpack such as roller balls, pinwheels, sticky snow, failing test slopes, and deep boot penetration.

    (1/4/2024)

    Small wet loose avalanches on the east side of Green Butte

    Photo: Cory Beattie

Avalanche Discussion

Yesterday's strong northeast winds kept upper mountain conditions locked up and cold. The strong winds have scoured most upper mountain slopes of any recent new snow, leaving heavily wind-effected surfaces. Due to the dry, and warm atmospheric conditions, wind transported snow is not accumulating on any surfaces. Instead, this snow is mostly melting and sublimating back into the atmosphere before it hits the ground. For more information on yesterday's conditions, see the observation from Old Ski Bowl HERE. 

Near and above treeline, there were few signs of significant warming, with most rock outcrops still holding on to the majority of its rime ice. Today, northeasterly winds are expected to drop significantly, increasing the warm-up factor for high elevation terrain. This will look like a variety of hazards:

  • Wet loose avalanches. As surfaces finally warm, expect to see signs of a destabilizing snowpack. These avalanches will look like point release, loose avalanches, entraining snow and fanning out in the runnout. For the time being, these avalanches are expected to be relatively small and resistant to trigger. However, instability could increase over the next 36 hours if temperatures continue to climb. 
  • Ice/rock fall. Most cliff bands (i.e. Shastarama, Red Banks, Casaval Ridge, Trinity Chutes) are covered in thick rime ice that is ready to shed once temperatures warm enough. This will likely happen today. If you're going to be around those areas, wear a helmet, keep your eye out for smaller chunks before it gets worse, and don't spend time hanging out below them.
  • Weakened cornices. This winter has built some large cornices across most ridgelines in the forecast area. These cornices will begin to weaken as temperatures climb. Some of these cornices are the size of small cars, certainly capable of hurting or killing someone if they fail. Give these cornices a wide berth as temperatures warm, trying not to put too much faith in their support.

The road to Castle Lake is closed. The Siskiyou County road department is down to one blower but will be working on clearing the road next week.

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