Text Box: How ice dams form: 1)   Roof shingles are warmed by heat from the sun and heat escaping from inside the home.  2)   Snow begins to melt upon contact with the warmed roof shingles.  3)   Melted snow travels along the roof’s slope to the gutter.  4)   Melted snow refreezes when it touches cold eaves and gutters. This ridge of ice is called an ice dam. Icicles form along the dam.