But they don't have to ruin your winter.
Ice dams are most current in northern climates that are subject to heavy snow buildups on roofs.
Ice dams occur when this heavy snow buildup melts during the day and then refreezes when temperatures overnight. After several days of melting-freezing cycles, it's common for the melted water and ice to work up under the shingles until water enters the attic and eventually does damage to the ceilings, walls and contents. The problem worsens because insulation loses its R-Value when it gets wet. In cases where the ice dam goes unnoticed for an extended period of time, there can be significant damage to the building and its contents. Each fall, thoroughly clean all leaves, sticks and other debris from your home's gutters and down spouts.