Salt River and Wyoming Ranges

Lawinenprobleme

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Possible

  Größe

  1.5–2.5

  Problems #1 and #2 currently have a complex and overlapping relationship. Two primary layers of weak snow exist in the top meter of the snowpack here (and could rest deeper in areas that receive more wind). A natural avalanche on Mt. Taylor likely failed on facets or a crust+facet combination buried from all snowfall accumulated after March 20th. I found this layer on Shadow Mountain on Sunday as well as in the Snake River Range yesterday, however, recent human-triggered avalanche activity has primarily involved a layer of weak snow buried ~ March 30th that is now 2-3 feet deep. Both of these layers have produced failure in snowpit tests and it is worth adding the observation of the activity of both of these layers to your toolkit where you are recreating. Observations are sparse when you put an entire mountain range in viewpoint; both layers of facets seem most common on the middle to upper-elevation slopes ranging NE-E-SE in aspect. We don't often deal with persistent weak layers so late in a season, and it definitely requires a mindset shift. Triggering a 2-3+' thick persistent slab avalanche will remain a possibility this coming week. You're most likely to trigger a slide involving this weak snow on very steep slopes (steeper than about 35 degrees) where the wind has built slabs in recent days and weeks. 

  In areas with a weaker snowpack, such as the Wyoming Range, deeper weak layers still remain a concern. Triggering a wind slab or persistent slab on layers in the upper half of the snowpack could step down to deeper layers resulting in a very large avalanche. 

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Likely

  Größe

  1–2

  Triggering a large avalanche is most likely where the wind has drifted the snow. Today's wind will affect upper-elevation and alpine terrain, and some exposed middle-elevation slopes. Expect to find these slabs in both obvious locations (such as near ridgelines) as well as in atypical locations that are commonly sheltered from the effects of the wind. Slabs also commonly form below cliff bands, on the aprons below steep couloirs, or at the base of cliffs where spindrift accumulates. Watch for evidence of windblown snow such as pillowed areas, dunes or ripples, or denser snow at the surface. Wind slab avalanches could break down into buried weak layers (see below), producing an even more dangerous avalanche.