Ice dams on your gutters risk injuring someone in your household, damaging the gutters, and even damaging the roof. This is why you need to take measures that prevent the ice dams from forming in the first place and not just wait to deal with them after the fact. Here are some measures for preventing ice dams from forming in your gutters:
Ensure the Attic Insulation Is Intact
Ice dams form on the edges of the roof if the interior heat rises and heats up the snow (on the roof) before the sun has the chance to heat it up. Since the edges of the roof (where the gutters are located) remain cold, the melting water collects behind the snow on the edges of the roof and freezes. This means anything that prevents the snow on the roof from melting or keeps the edges of the roof warm will prevent ice dam formation. A good way of preventing interior heat from reaching the roof is to keep the attic insulation intact at all times.
Install Heat Strips along the Gutters
There are heated cables or tape you can place along the gutters to warm them up. When the edges of the roof are warm and they free of snow, water (from the melting snow) will not find anything blocking its way; it will flow right into the gutters, into the downspouts and get drained away properly.
Don't Let Snow Accumulate On the Roof
You won't have an ice dam problem if you don't have any snow to melt in the first place. This is why removing snow from the roof as soon as it collects is another good way of preventing ice dam formation. Make sure you have the right rakes (such as those with safety rollers), and you can work safely (preferably from the ground) while removing the snow.
Minimize Interior Heat Sources
It also helps to minimize interior heat sources so that the snow doesn't melt prematurely. Any fallen snow on the roof should stay on the roof until either you remove it or they are molten by the sun (which melts even the snow on the gutters). Recessed lights are some of the most common causes of interior heat, make sure they are properly installed and insulated to prevent ice dam formation.
If your roof is experiencing a particularly bad case of ice dams, then it's time to call a roofing contractor to diagnose and fix the issue. It might be that there is a hidden problem on the roof, such as undiagnosed insulation problems, which the contractor will fix.
Check out a website like http://www.us-roofing.com for more information and assistance.