Wind-drifted snow

/Wind-drifted snow
Wind-drifted snow 2017-10-20T13:17:06+00:00

Wind is the architect of slab avalanches through the crea tion of wind slabs.

Tactics: avoid recent snow drifts

Duration: 1-2 days

Typical signs:

  • Signs of snow drifting
  • May be hard packed or soft
  • Irregular when breaking trail
  • Cohesive snow
  • Alarm signs (e.g. recent slab avalanches, cracking)

Typical distribution:

  • Wind shadows (leeside, terrain breaks, gullies)
  • Often found at high altitude and ridge areas
  • Variation within a small area

Tips:

  • Avoid when possible
  • Recent snow drifts are often dangerous over 30° of slope angle
  • Big differences in snow stability within a small area

Wind slab formation

  • Sufficiently strong winds. Wind speeds 30 – 80 km/h are the most effective.
  • Erodible snow surface or new snow.

Wind slabs may be hard packed or soft, often displaying highly uneven distribution in lee areas.