Central Sierra Nevada

Avalanche problems

• 

  Wet Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1

  A dramatic drop in temperatures should have allowed some of this week's wet snow to start to refreeze last night. As this wet snow continues to refreeze during the cold and cloudy weather the snowpack underneath the new snow should gain strength. On the other hand the new snow that fell last night and continues to fall today in some areas may not bond well to the melt-freeze crusts at first especially since many of the old snow surfaces may have frozen before the new snow started to fall. Some loose dry snow sluffs may become possible on steep NW-N-NE-E aspects and on some SE aspects wherever new cold snow has accumulated on top of frozen melt-freeze crusts. Areas north of Tahoe City will hold the best chances for these loose dry sluffs since they received more new snow. These loose dry sluffs should remain small and not entrain much snow due to the paltry amounts of new snow accumulation, but some of them could entrain enough snow to knock a person over or push them off course. These small loose dry sluffs could have larger consequences if they occur in or near terrain traps like gullies, cliffs, creeks, or other places that magnify the consequences of any size avalanche. 

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1

  Some wind slabs may have formed due to the combination of strong winds and new snow. These wind slabs will also sit above frozen crusts and may not have bonded well to those crusts. Most of these wind slabs should remain small and limited in distribution due to the amount of new snow available for wind loading. Even though many of these wind slabs should not involve enough snow to bury person, some of them could still be large enough to cause problems for backcountry travelers especially north of Tahoe City or in areas where terrain traps like the ones mentioned above exist. Wind loaded N-NE-E aspects and cross loaded NW and SE aspects in near and above treeline terrain north of Tahoe City represent the best places to find human triggerable wind slabs today. 

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Unlikely

  Size

  1

  Despite the colder temperatures, the strong April sun may be enough for some loose wet avalanches to occur on steep sun-exposed SE-S-SW aspects. If the forecasted cloud cover remains over the area these kind of avalanches should not happen, but if the sun breaks through onto some of these slopes where new cold snow exists some small isolated loose wet avalanches like point releases, roller balls, and pinwheels could occur.