Continental

Problemi valanghivi

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Possible

  Dimensione

  2.5–3

  Although avalanche likelihood is decreasing somewhat today, there is still concern about the buried weak layer of facets that formed on 1/26. We have had three avalanche cycles on this layer over the last several weeks, with periods of inactivity in between. These types of problems tend to linger for quite some time, as indicated by the recurring avalanches that we have seen. There will be a small possibility that a human could trigger this layer in steep wind-loaded terrain today. Specific leeward terrain features, steep gullies, and large cross-loaded slopes will be the areas where this problem exists. Consequences would be high if you triggered this problem. Hardslabs up to 3 feet thick could release across large pieces of terrain. Signs of instability will likely be absent with this problem; however, if you experience collapsing windslabs, you can expect conditions to be very hazardous. Users can reduce their risk by avoiding large connected alpine faces and slopes that have been previously loaded by wind. Given the brutal conditions out there, it should be an easy decision to stay off hazardous terrain today.  

  Wind slab: The winds we are currently experiencing have blown around very small amounts of remaining loose snow, creating a batch of fresher thin windslabs over the last couple of days. These are likely becoming stubborn or unreactive to human triggers, but you might be able to find small isolated pockets that remain unstable. Fresher windslslabs will be a bit softer and much thinner than the older ones described above.

   

   

   

   

  

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Unlikely

  Dimensione

  2.5–3.5

  A deeply buried weak layer near the ground remains a low-likelihood, high-consequence problem—especially in steep, rocky terrain and areas where the snowpack is thin or highly variable. Triggering this layer directly is unlikely at this time, but avalanches that start in the upper snowpack could step down to the basal weak layer.  There is a high degree of uncertainty regarding poor structure at the base of the snowpack.  What we can be sure about is that this layer is less of a concern in the Maritime zone and more so as you move towards the Continental zone where the snowpack is thinner and the weak layer is more developed. 

  Watch for thin spots near rock outcrops, scoured features, and along ridge tops. Wind loading adds stress to these shallow areas, and we don’t know where the tipping point is.