Once rain water freezes, water will no longer flow through your gutters, and layers of ice form. Snow and ice inside the gutters will expand until it overflows the gutters. Once the build-up of snow and ice in your gutters reaches the top edge of the gutters, most thawing will occur on the surface, which means that water will drip from the front and back of your gutters by day and will form into icicles at night when temperatures drop. Gutters will continue to be overwhelmed by melting snow from the roof, which will cause a thicker layer of ice to form above the gutter edge, and icicles will grow in size. This is the point at which ice damming becomes an issue because if the ice that forms inside your gutters backs up underneath the shingles, it is more likely to penetrate the roof decking, enter your home’s interior, and cause ceiling and wall damage.
