Summit Lake

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

  Continued snowfall this week has slowly added stress to the buried weak layer of surface hoar, which is roughly 1 to 2' deep in the Summit Lake area. While we haven't seen any recent avalanches on this layer, we have seen concerning snowpit results in some locations. The most likely place to find this layer is between 2000 to 3000' in sheltered terrain. Sometimes buried surface hoar provides red flags like collapsing or shooting cracks as signs it is unstable. However, it is also possible to trigger an avalanche on this layer without any obvious signs of unstable snow. 

  To avoid this problem you can always stick to low angle terrain and avoid steep slopes overhead. If you choose to enter steeper terrain you can improve your safety margin by avoiding large start zones and terrain traps like gullies or cliffs in the runout zone. There is a lot of uncertainty about how widespread and how sensitive this weak layer is in Summit Lake, which makes for a challenging decision-making setup. We recommend a conservative mindset to manage the uncertainty with this weak layer.

  Wind Slab Avalanches will become likely if winds pick up this afternoon. With plenty of soft snow on the surface from the past few days of snowfall wind slabs can form rapidly at upper elevations. 

  Loose Snow Avalanches will become more likely if the sun pokes through the clouds today. Be on the lookout for steep solar aspects if the clouds break up during the day, especially on slopes with trees or rocks that will heat up quickly.

  Cornice Fall: Cornices have been growing during the active weather over the past week. These can release naturally and may trigger larger avalanches on slopes below. Limit spending time below cornices, and give them plenty of space if you are traveling along ridgelines.

  

• 

  Glide Cracks

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  2–3

  During the brief breaks in cloud cover this week we have observed continued glide avalanches releasing across the forecast zones. This is part of the normal spring shed cycle, but these avalanches are unpredictable and very difficult to manage with limited visibility. The best way to avoid them is to steer clear of steep terrain overhead. If visibility allows, try to keep an eye out for glide cracks opening up that are often a precursor to avalanches releasing. 

  Wet Slab Avalanches: Underneath the new snow from this week the snowpack has largely transitioned to spring wet snow at low and mid elevations on solar aspects (east, south, west). On Fresno this week we found concerning structure in the wet snow layers, with multiple tests failing in a layer of wet faceted snow about 2' deep in the snowpack. If the sun comes out today we could see a rapid transition back to wet slab avalanche problems. Especially on steep south-facing terrain with trees or rocks poking through where the heat from the sun can quickly melt the snowpack. If the crust on top of the wet snow melts and you are sinking in deeply to wet snow while traveling this is a clear sign to avoid avalanche terrain.