Mount Shasta

Problemi valanghivi

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  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Possible

  Dimensione

  1–1.5

  Temperatures have dropped below freezing. However, it likely won't be enough to abate wet snow instabilities, especially for the Eddy Mountains and at lower elevations, where temperatures have remained warmer.

  Yesterday, the snowpack showcased its weakness with a natural cornice collapse and a wet loose avalanche off Middle Peak at Castle Lake. As daytime warming occurs, minimize time spent beneath corniced slopes and give them a wide berth when traveling above or below.

  Today’s sun exposure will thaw surface crusts and further weaken steep, sunlit aspects—particularly those punctuated by rock outcrops, where radiative heating will cause the surrounding snow to soften more quickly. Terrain features that funnel snow, such as chutes and gullies, are prime locations for wet snow to become problematic. Natural signs of instability, such as rollerballs, may be less obvious due to the already saturated or crusty surface conditions. However, sinking past your boot tops in soggy snow or being able to squeeze liquid water from a snowball are additional signs that the snowpack is not supportable. When in doubt, steer around areas harboring uncohesive snow surfaces and seek mellower and more supportable terrain.

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Possible

  Dimensione

  1–1.5

  A few inches of new snow in the alpine and variable wind directions may have been enough to form small pockets of wind drifted snow across many aspects. The most likely locations will be in extreme terrain directly below ridgelines, rollovers, and rock outcrops. Pay attention to where blowing snow has accumulated, and use surface texture and wind lips as clues to determine loading patterns. Shooting cracks underfoot indicate a reactive drift. Even small avalanches in large terrain can have severe consequences. 

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Unlikely

  Dimensione

  2–2.5

  Avalanches failing on a buried graupel layer about three feet deep continue to present a low-likelihood, high-consequence scenario. Earlier this week, after a period of rapid loading, a large avalanche in the Old Ski Bowl released naturally on this layer, which sits above a crust. 

  It is unlikely that a human or machine could trigger this layer. The primary concern is meltwater moving through the snowpack and pooling on the crust, weakening the graupel to the point of failure. While unlikely, the consequences of such a slide would be severe, and we cannot completely rule out the possibility. For this reason, the problem remains listed.

  Stability tests have shown this layer to be unreactive. However, due to the dynamic effects of water within the snowpack, there is no definitive way to eliminate this concern until freezing temperatures re-strengthen the snowpack. This process has already begun but will take another couple of nights before this layer completely freezes. 

  Meanwhile, use caution on steep slopes near and above treeline. Consider avoiding terrain below cliff bands where graupel may have accumulated. As always, evaluate the consequences before committing to steep terrain, or choose conservative terrain options and allow the snowpack more time to adjust.