Continental

Avalanche problems

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Wet Loose avalanches will be a concern today, and for the rest of the season.    The sensitivity of this layer goes through peaks and troughs throughout the day, depending on the temperature and the sun's effect.  Avoiding this problem is easy if you know what to look for.  

  Heavy new snow that fell last week has already gone through a wet loose shed cycle during clear weather on 4/19, making wet loose activity less widespread than what we saw last weekend.  Cloudy skies will prevent wet loose from becoming significant today, however, most areas only received a minor freeze if any, which will break down quickly if the sun is able to break through the clouds.  

  Wet loose activity can be assessed by how wet the surface snow is and how steep the terrain is.  When there is more than 6 inches of wet snow at the surface and the slope angle is greater than 35 ° wet loose activity will be likely.   Remember this includes the slope above you as well as the one you are traveling through.  Roller balls off steep rocks are an early sign that wet loose is becoming active.

  It is recommended to plan your route to avoid steep slopes during times of day when they may be susceptible to wet loose activity.  East slopes are the first to heat up,  as the day progresses, South aspects will become active and finally West aspects will become prone in the afternoon/evening.  Avoid travel in steep terrain on slopes that are heating up.  Pay attention to the terrain above you as well as the terrain that you are travelling through.

   

   

   

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3

  Unusual April weather with consistent cloud cover and precipitation has built a slab above a weak layer of snow that formed during extended high pressure in late March.  Heavy snowfall last week greatly increased the sensitivity of the slab with numerous close calls reported from Helicopter ski operations and the general public.

  Persistent slab concerns from last week have decreased in depth due to natural settlement of the slab and sensitivity is expected to be lower due to warm temperatures and time allowing some bonding to occur.  Even though cloud cover continues, precipitation has become very light allowing the snowpack to adjust and accept the April slab to some extent.  Triggering a large persistent slab avalanche 2-3+ feet in depth remains possible in high elevation north facing terrain that has remained cold.  

  Assessment for this avalanche problem is recommended on a slope by slope basis if choosing to travel in steep terrain.  Especially on slopes that are more complicated with convex features, rock trigger points and hanginging snow fields.  The depth of this layer will likely not give feedback such as shooting cracks or collapsing due to its depth.  The best way to assess a slope is by digging snowpits to identify the weak layer.  This process is time consuming and can often be misleading.  If you are unfamiliar, or do not want to go through this process, it is recommended to stick with more moderate and simple terrain.