Mount Shasta

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Over the past 24 hours, westerly wind has averaged 15 mph, ideal speeds for transporting the three to six inches of new snow and compacting it into dense wind slabs. Today, these slabs could be one to two feet deep.

  Your likelihood of triggering one of these avalanches will be highest above the treeline on slopes that face north, northeast, and east. That said, you may encounter them on southeast and south-facing terrain, especially in complex terrain with cliffs or gullies.

  Approach steep leeward aspects carefully. Pay attention to where blowing snow is accumulating; lookout for shooting cracks and feel for dense, hollow-sounding surfaces as indicators of wind slab.

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–1.5

  Sustained warm mountain temperatures combined with rain-on-snow expected up to 7,000+ feet today increases the likelihood of wet loose avalanches on all aspects below and near the treeline. As the day progresses, the drop in the freezing level—from 9,100 feet this morning to 6,700 feet this afternoon—will concentrate this problem below treeline.

  As water 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. 

  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 an indicator that wet loose instability is on the rise.