• An ice dam is an accumulation of frozen water in the gutter system and at the edge of the roof, preventing the subsequent runoff of melted snow from the roof/gutter system. Ice dams are common in areas with heavy snow accumulation. In most cases, frost starts inside the house when heated air seeps into an unheated attic. This phenomenon creates warm areas on the roof, causing snow to melt outside. Melting snow flows down the slope of the roof until it reaches the cold overhang, where it freezes again. The process continues, causing the ice to accumulate along the eaves and form a dam. Eventually, this dam forces the water to accumulate under the roof tiles and sometimes into the ceiling or wall inside the house. Ice dams can cause structural failure, corrosion of metal fasteners, and mold growth on attic and wall surfaces. Few homeowner insurance policies cover de-icing. However, the Special Hazard Form HO (HO 5) usually covers internal or external damage resulting from ice dams.