Clogged gutters negate their benefits. Depending on the geographic region, it can fill with leaves, pine needles, oak tassels, asphalt, and other shingle debris, and nests that harbor infestation. It can trap stagnant water in the debris and become a breeding area for mosquitoes. Dried debris, particularly pine needles, creates a potential fire hazard during drought conditions in areas prone to forest fires. In areas susceptible to winter conditions, clogged gutters cause dangerous icicles and water damming, forcing melting water to back up under shingles and leak into the interior. The still water around the foundation can freeze, crack and buckle causing extensive damage to the base of your home.