Continental

Problemas de aludes

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1.5–2.5

  Buried surface hoar continues to be the primary concern for users in the Valdez/ Thompson Pass area.  The depth of this layer varies depending on proximity to the coast with about 2 feet of settled storm snow above the layer in the Maritime zone decreasing to just about 4 inches at the northern extent of our continental zone.  Good stability has been repeatedly reported and observed along the Thompson Pass road corridor.  This layer is not expected to be reactive in the core part of our forecast area except for maybe isolated pieces of steep terrain.

  Despite good stability reported in the majority of our forecast area, human triggered and natural avalanches have recently been reported in more remote zones that have failed on the 3/16 buried surface hoar layer.  These include coastal upper elevations and glaciated valleys East of Marshall Pass.    This creates a dangerous situation where users could easily be lulled into complacency with prior stable results.  Don't let your enthusiasm for good snow and stable results carry over with you when traveling to new valleys or zones.  Remain diligent and assess the snowpack on a slope by slope basis in remote or unfamiliar terrain.  Natural settlement of the overlying slab, temperature increase, and wind can all increase cohesion, which can increase the sensitivity of this weak layer where it is present.

  Unfortunately, assessment of this layer can be challenging as hand pits may not reveal this layer.  Compression tests and Extended column tests do a better job of identifying this weak layer, but these can also be confusing and give false stable results.  Attempt to identify the new/old interface of the most recent snowfall, this has been fairly easy to do.  Once identified, look for faceted snow at this interface.

  Human triggered avalanches remain possible that would be large enough to injure, bury or kill a person.

   

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1–2

  Diurnal temperature swings have been increasing in high and low temps over the last several days.  This is slowly increasing the likelihood for wet loose avalanches to occur during the heat of the day on slopes being exposed to direct sun.  Overcast skies are expected today which will likely limit wet loose activity, however the sun will likely pop out at some point especially in the Continental zone.  Sun and temperature crusts have formed on solar aspects that will initially prevent wet loose activity.  Once the heat of the day breaks down these crusts wet loose activity will become possible.  The first area to become active will be steep rocky terrain where the suns energy is more effectively absorbed by the dark color of rocks and then transmitted into the surrounding snow surface.  Pay attention to where the sun is in the sky, wet loose hazard will peak on a slope when the sun becomes perpendicular.

  Wet loose activity is a secondary concern to problem 1 listed above.  Steep terrain that produces wet loose activity will also have the potential for slab avalanches to fail naturally or be human-triggered.   Avoid steep terrain that is being heated up by the sun.  Even small slopes can be dangerous if they are above terrain traps or exposure.  

  This is the time of year when snow begins to naturally shed off steep Southerly terrain.  Avoid exposure to these areas during the heat of the day.