February 2, 2017


Ship Creek & South Fork Eagle River:

Obvious signs of instability:

  • Numerous persistent slab avalanches from Monday-Tuesday wind event
  • Numerous “whumphs” collapses between 2500-3000′
  • Large persistent slab cracked out around us, but didn’t slide due to low slope angle


  • Sunny, temps in the 20s, calm wind

Surface conditions:

  • Variable, wind-affected snow: areas of supportable windboard, breakable windboard, and sheltered powder


Maps show widespread, natural persistent slab avalanche activity in the South Fork area from the Monday-Tuesday wind event.  Many of these avalanches propagated wide relative to their path, and all seemed to fail at ground on basal weak layers.  This is, hands-down, the most impressive avalanche cycle witnessed in South Fork in at least half a decade (this is only a partial documentation – many more aren’t flagged):

This is the avalanche (HS-N-D3-R2-O/G) in the N facing bowl of 3787:

These are avalanches (HS-N-D2.5-R3-O/G) off W aspect 4205:

This is where a half football field size persistent slab cracked around us (we were in the middle of slab – crack shown from bottom right corner of photo):

Ship Creek valley:

Eklutna Lake:

Naturally triggered (from Monday-Tuesday wind event) persistent slab avalanches in the Eklutna Lake area:

More natural persistent slabs in the Bold Peak valley area:

Natural persistent slabs around Bold Peak: