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.