Galena Summit & Eastern Mtns

Problemi valanghivi

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  1–2

  Natural and human-triggered wet loose avalanches remain possible. Tuesday evening, a wet loose avalanche hit the river beneath Carbonate Mtn in Hailey. The snowpack has not frozen solidly in 72 hours in some areas, so it will not take much daytime warming or solar input to melt the thin surface crusts that formed overnight. Once the crusts break down, there will be little snowpack structure on some slopes to keep you or your machine from falling into an unsupportable, soggy mess. Where are you most likely to find these soggy snowpacks?

  • Lower elevation terrain: Temperatures were and will be warmest near the valley floors, and the lack of wind here will not help matters. 
  • Rocky, craggy slopes sheltered from the wind: Steep, sheltered slopes with exposed rocks could produce wet loose slides, especially in areas with a snowpack less than a couple of feet thick.   

  Managing this problem is fairly straightforward: Steer clear of steep slopes after the thin surface crusts melt. Pay attention to the terrain above you; while natural avalanches are less likely than they were yesterday, they remain possible. Even small wet avalanches are surprisingly powerful, and wet loose slides make great triggers for the wet slab avalanches described below.    

   

  

• 

  Wet Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Unlikely

  Dimensione

  1.5–3

  The chances of natural and human-triggered wet slabs are decreasing, but we still have to consider this problem. I saw a fresh wet slab slide in the mountains near Smiley Creek yesterday (view report), and a handful of wet slab avalanches released in the afternoon near Hailey (view observation). Huge wet slabs like those that released on Sunday and Monday are unlikely today.

  The combination of last night's weak freeze and today's muted April solar input makes wet slab avalanches possible where you're sinking well into a wet snowpack. This scenario should be most widespread at lower elevations and on slopes directly facing the sun that are protected from the wind.

  Wet avalanches do not need human triggers to occur; they release on their own far more frequently than dry avalanches. Accurately predicting slope-scale stability for this wet slab problem is difficult at best. 

  How do we manage this problem? Unfortunately, avoidance is the only reliable strategy. You can minimize your risk by avoiding large or consequential avalanche paths where you are falling deep into a wet snowpack. A thin surface crust will not entirely eliminate the chances of triggering one of these slides. 

  ADDITIONAL DISCUSSION: Don't trust cornices while the warm weather is making them sag, bend, and break. Most of them froze overnight, but it will take more time for them to freeze solidly. Give cornices plenty of space if you're traveling on ridges.