Bulletin d’avalanche

Mount Shasta

Mount Shasta Avalanche Center
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Danger d’avalanche

Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 6 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Strong southeast winds and new snowfall will continue to load and cross-load most aspects near and above treeline. Large wind slabs may be possible to trigger on slopes steeper than 35 degrees on wind-exposed terrain features near and above treeline. Conservative travel and careful snowpack evaluation will be essential to avoid mishaps. Seek simple, wind-sheltered terrain to minimize your exposure to this hazard and to find the friendliest conditions.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Southeast winds have hammered the forecast region over the past 24 hours, transporting large amounts of snow. Today, the snowpack will undergo additional change and loading from both wind and new snow. A cold-to-warm storm trend will deposit denser snow over lighter snow, creating an upside-down snowpack structure. This additional load may push stability toward a more reactive and potentially dangerous state.

    Wind slabs ranging from several inches to multiple feet deep are possible to trigger and may release naturally on leeward south, west, and north aspects near and above treeline. Small, isolated drifts may form in exposed areas below treeline. Slopes holding wind-stiffened surfaces that appear lens-shaped and sit below ridgelines, rollovers, and rock outcrops should be avoided or carefully assessed and managed. Shooting cracks, recent avalanches, and active blowing snow are clear signs to change aspects or choose mellower terrain. Windward and scoured slopes will generally offer the safest travel conditions.

    Storm slabs may develop if more than 6 inches of new snow accumulates. Monitor new snow totals and surface cohesion as you travel. Use small, inconsequential test slopes to evaluate the snow’s stability. 

Avalanche Discussion

If today's weather and snow totals verify, conditions will get worse before they get better. However, if they don't, be prepared to self-assess and travel accordingly. 

Recent observations from the Eddy Mountains and Mount Shasta have identified reactive wind slabs failing at the old/new snow interface. In addition, yesterday's observation from the Old Ski Bowl found multiple graupel layers buried in the upper portion of the snowpack. Stability tests did not propagate, however, compression tests and hand pits indicate that these layers are reactive and prone to movement. 

With ongoing loading, stormy weather, and suspect weak layers, there's uncertainty regarding how sensitive the snowpack may become. For this reason, it's a good day to reel in your slope angles, use conservative travel methods, and not forget about overhead hazards.

Snow depths remain shallow on the west side of the forecast area. Visible and shallowly buried obstacles are abundant, as are open streams. Ski and ride with caution. 

Tree fall is a real hazard with strong to extreme winds this weekend. It would be prudent to avoid traveling in areas with standing dead trees.

Events this weekend:

We hope to see you there!

Régions couvertes