Attached with clips along the roof's edge in a zigzag pattern, heated cables combat ice dams that lift shingles and cause leaks. This solution allows you to equalize your roof's temperature by heating it from the outside instead of blowing in cold air from the inside (as we mention next in "Fast Fixes"). Just be sure to install the cables before bad weather hits.
For more information on this and other electronic snow and ice melters, see Plug-in Snow Busters
Keep reading for fast fixes you can do yourself after a dam has already formed.