Continental

Problèmes avalancheux

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1.5–3

  The snowpack currently holds multiple interfaces of concern, with the most likely issue being weak faceted snow in the upper snowpack. In wind affected terrain, this weak snow is capped by fresh wind slabs, while in more sheltered areas it is buried by recent snow from 3/19–20. These weak interfaces are expected to slow bonding and allow instabilities to linger longer than normal. Recent wind has created highly variable surface conditions, so there is not one consistent setup users can look for across the forecast area. The most likely depth of instability is in the upper 1–2 feet of the snowpack.

  This variability makes the snowpack difficult to assess and easy to misread. Users can reduce risk by choosing simple terrain and avoiding terrain traps.

  A second, lower-probability concern is the 1/26 facet layer, which is buried around 2 feet deep in many areas. This layer has not produced any known avalanche activity in the last few weeks, and stability tests have generally shown decreasing sensitivity, but we are not ruling it out. A smaller avalanche in the upper snowpack, or warming temperatures in the coming days, could add enough stress to cause this layer to fail and produce a larger avalanche.

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–3

  Wet loose avalanche activity is beginning to emerge and should be taken seriously. Below average temperatures and strong winds have delayed the normal spring shedding process, leaving many slopes cold and dry later than usual. As temperatures slowly return to seasonal norms and winds ease, this change will place new stress on a snowpack that has not seen meaningful warming in quite some time.  Expect south facing slopes with soft snow to become active during the heat of the day.

  This warming trend is the first notable stress the snowpack has seen in quite some time. In areas where the snowpack remains weak and faceted, wet loose avalanches may gouge deeper than expected and could trigger larger avalanches. This hazard is expected to increase through the week as winds continue to subside and daytime temperatures rise.

  Users should pay close attention to how the sun is affecting the snow surface. Roller balls and wet surface snow are clear signs that instability is increasing. Move to shaded terrain or lower angle slopes if the snow surface becomes wet or wet loose activity is observed. Overhead hazards such as steep, rocky solar terrain and cornices should also be avoided.

  

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  2.5–3.5

  Weak snow near the ground is increasingly common as you move North through our forecast zones, with the Continental zone being the most concerning. Although it still remains unlikely to trigger this layer, areas that have been scoured from strong northeast winds now have a shallower snowpack, making this layer closer to the surface and potentially easier for a rider to trigger.

  This is a low-likelihood but high-consequence problem most likely to be triggered in steep, rocky terrain and areas where the snowpack is thin or scoured. 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 the poor structure at the base of the snowpack.