Hatcher Pass

Problemi valanghivi

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Unlikely

  Dimensione

  1.5–2.5

  This problem is the definition of a low-liklihood, high consequence situation. The weak layers of concern are buried deep and will be difficult to trigger, but if you find the spot, the consequences of an avalanche will be huge. 

  While avalanches large enough to injure or kill would be surprising, there is a remote possibility (unlikely) of avalanches in specific terrain. 

  Since last week's significant storm, the snowpack has continued to settle and adjust to its new load. A strong cold snap helped lock in newer instabilities in the upper snowpack and recrystallize the surface a bit. However, poor structure and the potential for propagation on deeper, weaker layers that formed early season continue to be a remote possibility. These will be hard to find and trigger because of the depth of the weak layer. Riding a snowmachine will have more force and affect on these deeper weak layers, increasing the potential for triggering an avalanche. 

  Unlikely means improbable, not impossible. There remains a remote possibility of triggering a deep persistent slab 3-6' deep on leeward aspects or locations with a deeper snowpack. Human triggering or remotely triggering a large slab will be more possible with a large load (snowmachines) on slopes 30 degree and steeper at mid and upper elevations. The structure that is creating this problem isn't changing anytime soon. As settled weather and clear conditions continue through mid-week, continue to approach new terrain with a cautious eye. 

  Remember that deep persistent slabs (DPS) are unpredictable and often give infrequent feedback. Human triggering can happen days or weeks after a storm. These avalanches can be remotely triggered in isolated locations from flat terrain and have unusually wide propagation.

  PERSISTENT SLABS:  At low elevation and on shallower windward aspects, less snow depth exists. It will again be unlikely to trigger persistent slab avalanches 1-3' deep in terrain 30 degrees and steeper in these locations. 

  Due to the road closure, we have not gathered a lot of information above 3000'.  Riders are beginning to get out and test new slopes, so far without incidence. Our confidence remains moderate with this avalanche problem. Considering the potential high consequences of this avalanche problem, we recommend a conservative approach to terrain management.

  When the avalanche problems are complex and some uncertainty exists, it’s time to focus on safe travel protocol. In avalanche terrain, only expose one person to steep slopes at a time, choose safe zones out of the reach of avalanches for grouping up and expect avalanches to run further than you think, always have a spotter in a safe location, everyone carries a beacon, shovel, and probe, and are prepared and practiced for companion rescue.