Strong winds and hailstones the size of golf balls battered Rock Hill in South Carolina, USA.<br /><br />Chris Mazza and his family were at home preparing for their mum's birthday when the storm hit on Saturday. (20/4) <br /><br />Dramatic footage shows family's backyard covered in hailstones and debris swirling in the air. <br /><br />The storm also downed trees and power lines across York County, leaving 4,800 residents without power.
