It drifts onto sheltered places such as lee slopes, gully tops and corrie rims. Winds usually start drifting snow at around 15 km/hr (10mph) but the real action happens at 25 to 80 km/hr. (15 to 20 mph). Wind can transport light, fluffy snow more easily than old, hard snow. The amount of potential wind-blown snow is called " snow available for transport".