Mount Shasta

Problèmes avalancheux

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–2

  Powerful south to southwest wind and about six to 10 inches of new snow above 8,000 feet will make triggering a wind slab avalanche possible today. The wind will blow moderate amounts of snow onto leeward aspects above treeline over the next 24 hours. At 6,000 feet, speeds will be 10 to 20 MPH, while at 10,000 feet, the wind will howl at 35 to 45 MPH.

  You'll be most likely to find wind slabs on north, northeast, and east aspects. Though, you may find the wind has crossloaded snow into slabs along the sides of gullies on northwest or southeast facing aspects, as well. The leeward sides of trees and the along the sides of gullies are common terrain features that serve as catchment areas that may harbor deep accumulations of wind transported snow.

  An avalanche today could be several feet deep and may not be survivable. Use caution if traveling on any of the shaded aspects of the compass rose steeper than 30°. Look for drifting, shooting cracks, and collapsing; listen for hollow, drum-like surfaces; and feel for density changes from soft to firm or shallow to deep.

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–1.5

  While last night was cooler than the night prior, temperatures below and near the treeline were above or just barely freezing. The Castle Lake weather station recorded a low of 36° Fahrenheit and the weather station on Gray Butte recorded a low of 31° Fahrenheit.

  As rain and water from melt, works its way through the snowpack, it can exploit any weak layers and trigger an avalanche that starts small and then grows as it entrains more wet snow moving downslope. These avalanches can be small yet mighty, as they could carry you over hazardous terrain such as a section of cliffs or down into trees.

  If you observe roller balls or if you're sinking deep into wet snow when you step off your sled, skis, or board, this is a big indicator that wet loose instability is on the rise. Use care when traveling on steep slopes today, especially near hazardous terrain features.

  

• 

  Cornices

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–1.5

  Today is slightly cooler, but with temperatures still near or above freezing, additional loading from wind, snow, and rain, these cornices are still not to be trusted. Most cornices around the forecast area are on the north and east sides of ridges, but because of differences in terrain and how the wind moves through the mountains, you could find them on any aspect.

  Cornice fall can be tricky to predict as they often fail without notice. This time of year, especially during warming periods, is when they are most likely to fail. The best way to prevent being crushed by one of these burgeoning beasts is to avoid or limit your travels beneath them, staying much further back from the edge of ridges, and keeping bare earth or trees between you and the edge.