Continental

Avalanche problems

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  The most recent snowfall from 2/27-28 has been found to be 6-10 inches in depth and overlies old wind slabs in some locations and older storm snow in more protected locations.  Good bonding was observed at the interface of the new snow and the wind slabs underneath the new snow have been showing signs of being unreactive.  Another night of settlement, calm -light winds and light-no snowfall will allow stability to continue to increase.

  Human triggered avalanches are possible up to 1 foot in depth in steep rocky terrain, steep convex features and areas where wind has stiffened the snow surface.  An inch or two of new snow is expected today, but is not expected to be enough to increase the avalanche hazard.

  Hand shear pits and small incosequential test slopes are great tools with the current conditions to quickly gather information about the snowpack in the area you choose to travel.

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1.5–2

  There are currently 2 persistent weak layers on our radar, both only exist at low elevation.There is a layer of buried surface hoar from Valentine's Day as well as weak snow below a decomposing rain crust from late January.

   Below 1500 feet a rain crust is buried 12-16 inches, and has shown reactivity in recent observations. Collapsing and propagation in ECTS from multiple locations have been taking place on this layer within the last few days. Currently, we have not seen any avalanche activity on this layer, but that is becoming increasingly possible with continuing snow/rain loads as well as further weakening of the old rain crust. 

  Buried surface hoar from 2/14 exists in wind protected areas from 1500 -2500 feet.  Burial depth in the maritime zone is around 2 feet and a bit shallower moving inland. This layer showed reactivity in pit tests earlier this week with clean shears in ECT tests. So far we are not seeing propagation or avalanche activity on this layer but that may change with continued stress.  

  To limit exposure to both of these layers avoid terrain traps and  consider using conservative terrain while moving through low elevations..  There is uncertainty on the current and future reactivity of these two layers. We are keeping these on our list, as current weather conditions will continue to stress these layers. 

   

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Above freezing temperatures at low elevation coincided with direct sun yesterday.  This combination created a moderate amount of wet loose activity with low volume.  A crust will now exist on south aspects at low and possibly mid elevations that will limit wet loose activity until it is broken down by above freezing temps, rain , or direct sun.  Rain or direct sun will have the greatest effect on the crust and potential for wet loose activity, and the presence or absence of either of these will determine the amount of wet loose activity that occurs today.  Pay attention to the weather, and how frozen the surface snow is at low elevations.  Wet loose activity will begin near rocks first as these heat up quicker than the snow surface and transfer that heat energy into the nearby snow.

  When assessing wet loose hazards, it is essential to take the hazard in relation to the terrain you are exposing yourself to.  Are there terrain traps? Are there consequences if I were to be swept off my feet by even a small avalanche? 

  The size and shape of the terrain above you along with the amount of loose snow available to slide, directly correlates to the size of the wet loose activity that can occur. Terrain traps and exposure below you compound consequences.