Central Sierra Nevada

Lawinenprobleme

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Possible

  Größe

  2

  Even though wind slabs should have become more difficult to trigger today due to settlement and consolidation over the last 24 hours, some human triggered wind slab avalanches may remain possible in heavily wind loaded areas. Most of these wind slabs should remain less than 2 ft in depth but some larger slabs that measure 2 to 4 ft in depth could exist in isolated areas. While wind slabs may exist on any wind loaded N-NE-E aspects and cross loaded NW and SE aspects, the most sensitive wind slabs will linger in places like couloirs, unsupported slopes, steep wind loaded terrain, cliffy areas, and other complex or extreme terrain. If wind slab avalanches occur on slopes where the near crust facets exist, they could step down to this older weak layer.

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Possible

  Größe

  3

  The loose weak layer below the old crusts (near crust facets) on the NW-N-NE aspects has 1-3 ft of snow on top of it in most places. As this new snow consolidates, it will become more slab-like while the near crust facets will remain weak. These changes may mean that breaking the near crust facets could become easier in days to come. Human triggered persistent slabs will remain possible in some areas on the NW-N-NE aspects above 8000 ft. where these near crust facets exist. Larger triggers like the wind slabs mentioned above, cornice failures, or multiple people on a slope are more likely to cause a failure in this layer. Any avalanches that fail on this weak layer will be large, involving all of the snow accumulated since March 25th. These kind of avalanches can fracture across longer distances and in areas that do not typically slide.