March 7, 2017


Crow Pass – Raven & Milk glacier areas:

Obvious signs of instability (red flags):

  • Very small (D1), isolated, natural loose snow avalanche triggered on steep southerly aspect by sun warming snow on rock midday (snow dropping from warm rock triggered dry sluff, not wet)
  • Very small (D1), isolated, human triggered wind slab pockets on steep (40*+) southerly aspect near leeward ridge
  • Low volume, fast moving human triggered loose snow avalanche (dry sluff) on steep (40*+) southerly terrain
  • Active wind loading from increase in northerly winds by late afternoon


  • Clear, sunny skies with alpine temps in the single digits and light northerly winds increasing to moderate by afternoon (active, widespread wind loading by late afternoon – evening)

Surface conditions:

  • Relatively smooth, supportable, very firm windboard on steep exposed terrain
  • Uneven, supportable, firm, sastrugi windboard on less steep exposed terrain
  • Breakable windboard in transition areas
  • Carve-able wind-crusted powder in somewhat sheltered areas
  • Soft recycled powder in sheltered areas
  • Isolated, small patches of thin, breakable sun crust where scoured (sun crust is from a prior high pressure system)


  • Several days old, natural wind and persistent slab avalanches up to D2.5 on multiple aspects (some near or crossing Girdwood side Crow Pass trail)
  • Natural persistent slab avalanche (HS-N-D2-R3-O northerly aspect ~3500′) above Crystal Lake and the Crow Pass cabin: