Maritime

Avalanche problems

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Wet loose avalanches have been a concern over recent days as temperatures have been above seasonal norms, and a couple of days of direct sun have been affecting new snow on solar aspects.  Wet loose activity is expected to be limited today as a melt freeze crust likely exists on solar aspects, and overcast conditions are expected.  If rain occurs at low elevation expect for wet loose activity to occur.

  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.

   

  

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1–2

  Today's avalanche hazard will depend on the amount of new snow that falls during the day and the accumulation rate.  Moderate to strong SE winds are expected to accompany this snowfall, creating deeper pockets of snow near high elevation ridge lines that are more sensitive.  Areas that receive less than 8 inches of new snow and are unaffected by SE winds will remain in a Moderate hazard level.

  Expect for instabilities to arrive as our snowpack receives a new load of snowfall.  6-12 inches of snow is expected for our area.  The timing for this new snow looks like it will mostly occur during the evening -overnight hours.  A considerable rating has been applied at upper elevation due to the uncertainty of the timing and amount of the upcoming snowfall.  Solar aspects with a melt freeze crust may not bond as well initially.

  Pay attention to how much new snow has accumulated and how much wind redistribution is occurring.  Small inconsequential test slopes and hand shear pits are helpful tools for quickly gathering information.  Watch for signs of instability, such as shooting crack and collapsing, that would indicate the snowpack has the energy required to produce an avalanche.

• 

  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 are believed to be limited to terrain below 3000'.  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. New snowfall will add more stress to these layers and may increase the reactivity of these layers in the specific elevation band where they exist.

   Buried surface hoar from 2/14 exists in previously wind protected areas from 1500 -2500 feet.   This layer is difficult to identify as it has only been found in a narrow elevation band and exists in terrain that was protected from the strong outflow (North) wind event that occurred in late January.  This layer has been found on average between 12-20 inches in depth.

  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 observed. Currently, we have not seen any avalanche activity on this layer.

    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.