In Loonan Lbr. Co. v. Wannamaker (81 SD 51, 131 NW2d 78 [1964], was dealing with injury sustained from a rock propelled by a lawnmower. plaintiff's window was damaged by a rock propelled from a lawnmower. In finding the operator negligent, the court concluded that the operator was mowing in an area with numerous rocks and stones and the operator was aware of the presence of loose rocks and that, being so aware, he knew or should have known that a power mower could pose a danger to surrounding properties.