Hail
The granular surface of a composition shingle's protective coating is what protects its underlying asphalt. When hail (3/4″ to 2″ in diameter) strikes a composition shingle, it destroys the protective layer as well as the asphalt coat and fiberglass mat in some cases. Metal accessories are dented, wood shingles and wood shakes are punctured, and skylights, A/C vents, siding, gutters, downspouts, windows, window beads, and screens are all susceptible to damage.