Heat tracing is a method of keeping outside piping
and other in-line equipment from freezing
when the media going through the pipe is water
or anything else which freezes within the seasonal temperature
The basis of operation is that an electric current passing through a resistor will create heat. Heat tracing is in the form of a cable that is wrapped around the pipe and other items. Inside the cable are two conductors with a resistive barrier separating them. This way, heat generation is spread evenly along the length of the cable.
Cable is selected on the basis of the amount of heat output required and the temperature it needs to reach. The current flow through the heat trace cable is controlled by a thermostat.
You can also set up heat trace cable to melt the snow off your roof if you are worried about the snow load. Of course, you would have to set up the heat trace cable before the snow comes.