This is called downwash—the powerful blast of air pushed downward by a helicopter’s rotor blades. What you’re seeing here is the Bell 407 at Grenchen Airport creating a textbook example. When a helicopter hovers close to the ground, its rotors generate a vertical airflow strong enough to kick up dust, water, debris, or even knock over nearby objects or people. In this footage, it becomes dramatically visible thanks to the moist surface, letting us literally see the airflow as it spreads out like