A technique for protecting a structure from an impact with ice involves providing a horizontal spall initiator extending from the wall a distance of 1 to 10 cm, the horizontal spall initiator being resilient to the ice impact, and formed by blade segments having a blade width less than ½ a thickness of an expected hard zone of the ice; and situating the horizontal spell initiator at an elevation of the expected hard zone. Situating the horizontal spall initiator at an elevation of the hard zone may involve providing an elevation control mechanism (e.g. buoyancy, mechanical, or hydrodynamic), or may involve a panel with a plurality of horizontal spell initiators at respective elevations. The horizontal spell initiator may be driven.