Pittsburgh residents should be aware of the potential for ice dams forming on rooftops due to the recent weather forecast, which predicts fluctuating temperatures. Ice dams occur when snow on a roof melts and refreezes at the edge, creating a barrier that can cause water to back up and seep into homes, leading to significant damage. The forecast indicates that temperatures will vary significantly, leading to cycles of melting and freezing, which exacerbate the risk of ice dam formation.