Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
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Pericolo valanghe

Wed
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
4 · Forte
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The storm is in session. High avalanche danger exists on all aspects and elevations. A large new snow load and strong southerly winds have paired up to create dangerous avalanche conditions. Traveling in, near, or below avalanche terrain is not recommended. Sticking to low-angle slopes with conservative and concise travel techniques will be the greatest asset for safety today.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5

    A strong south and southeast wind has installed drifts on wind-exposed leeward slopes and are most pronounced at the upper elevations. You will most likely encounter these drifts near or below ridgelines, rollovers, or wind-exposed features such as gullies and depressions that have had time to collect drifted snow. Accompanying the wind, copious amounts of snow will increase the sensitivity and size of these drifts thought out the day. Drifts remain possible in any location that receives consistent wind loading, so it's important to not become complacent towards certain areas. Be on the lookout for shooting cracks and recent avalanche activity indicating unstable snow and to avoid such areas.

    (3/27/2023)

    2023.03.27 snow being transported onto leeward slopes near and below treeline. 

  • Storm Slabs

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

    One to three feet of new snow will fall on a variety of surfaces, the majority of which will act as a good bed surface for snow to slide on. As snow amounts rapidly accumulate, so will the chances of triggering a storm slab. Luckily, you can drastically reduce that risk by avoiding being on or near slopes steeper than 30 degrees. Terrain management is key. Storm slabs usually break over convex rolls or along shallow areas like cliff bands or ridgelines. With cold temperatures present in the mountains, storm snow will not have the chance to bond easily and will be pushed over its threshold as addition snow is loaded. Heed to natural signs of instability such as recent avalanches and shooting cracks.   

    (3/25/2023)

    Cracking within the new snow is bulls eye evidence that a storm slab problem is lurking.

    Photo: N.Meyers

  • Loose Dry

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

    Dry-loose avalanches will become a problem due to the sheer amount of snow and the inadequate time allowed for the snow to bond. This problem is likely to occur on any slope steeper than 30 degrees or areas where snow is being pushed downhill. A dry-loose slide may additionally cause storm slabs or wind slabs to release and result in a much more significant and traumatic avalanche. Dry-loose snow will want to pile up in concavities or narrow spaces, so identifying and avoiding terrain traps will greatly aid you against this problem. 

    (2/27/2023)

    Dry-loose snow sluffing off rollover and pilling up below treeline.

    Photo: E.Falconer

Avalanche Discussion

As another storm crashes down on Mount Shasta, it's important to dial it back and adopt an assessment mind state. Observations before the storm have discovered many crusts layers in the upper portion of the snowpack with varying distributions throughout the forecast zone. Some of these crust do not present a sound snowpack structure and could become problematic with this new load.  

  • Everitt Memorial Highway is CLOSED
  • Castle Lake road is CLOSED
  • Pilgrim Creek Snowmobile Park - OPEN
  • Deer Mountain Snowmobile Park - OPEN
  • MS Ski Park/Nordic Center - OPEN

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