Galena Summit & Eastern Mtns

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3

  The weak snow buried near the ground continues to be the primary avalanche concern in this zone. While encountering a wind slab (described below) is more likely, any wind slab you trigger has a good chance of "stepping-down" to the weak snow near the ground. This layer has produced both human triggered and natural avalanches in this zone in the past few days:

  • Saturday, a skier on Titus Ridge intentionally triggered a large avalanche. The slide initiated as a stiff wind slab that formed during last week's wind event and then "stepped down" to the December weak layer. Photos and more details are available here. I looked at the slide that same afternoon—watch the video I made.
  • Sunday, Sun Valley Heli reported seeing a recent large, natural avalanche that failed near the Baker divide, likely involving this weak snow (photo here).

  The depth of the snowpack is highly variable in this zone. This is important because the more deeply this weak snow is buried the more difficult it is to impact. Conversely, in areas where the snowpack is thinner, the weak layer is much more "accessible" to a skier or rider. Last week's prolonged wind event stripped many slopes (bringing the weak layer closer to the surface) and deposited hard slabs on many others (adding weight to the weak layer).

  Snowfall over the past few days has masked the obvious signs of what happened during the wind event, making it nearly impossible to determine what happened during that event on any given slope. This high degree of variability has created a snowpack who's behavior is difficult to predict. This fact has kept many experienced skiers and riders from entering into consequential avalanche terrain. 

  So what sort of areas should you be most worried about right now? The avalanches described above share a number of characteristics: they failed in steep (over 35 degrees), rocky, wind-affected terrain. This is exactly the type of terrain where you are most likely to encounter this problem today. 

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1–2

  Two weeks ago, the combination of several inches of new snow and wind was enough to produce a number of very large avalanches in this zone (photo here). These slides failed in wind-loaded areas, often involving layers of weak snow. Yesterday, this zone received 4-10" of low-density snow, with the highest amounts reported in the area around Galena Summit. The Upper Titus weather station is reporting light winds, but observers yesterday reported winds blowing and transporting snow on Mushroom Ridge, in the Baker Creek drainage and the Boulder Mountains. You are most likely to find a sensitive wind slab in areas where more snow has fallen and where the wind has been building slabs. Remember that even small slides can have high consequences if they carry you through rocky, treed terrain or push you down into a terrain trap like a gully or a creek bed. In addition, these slabs will be adding weight to the persistent slab problem described above. 

  ADDITIONAL DISCUSSION:Cloud cover looks to be variable today, with periods of clouds and sun. As we trend towards the spring and the sun climbs higher in the sky the intensity of solar radiation increases by the day. It doesn't take too much sun for the snow surface to melt, creating the possibility of loose snow avalanches in steep terrain. This problem is fairly simple to manage—if the sun comes out be aware of the terrain you are exposed to from above.