Quote from Al in Brother, Can You Spare a Hot Rod?
Al: Tim... Blocked roof gutters can form an ice dam, causing the water to back up under the shingles and leak into the house.
Tim: You can melt the ice and prevent it from refreezing using Binford's new heating coils. Now, they're very simple to install. If Marv will come in here and take a look at this. Little clips are fastened underneath the cable, and there underneath your shingles, just like so.
Al: Now, once they are properly in place, they are guaranteed to work every "shingle" time.
Tim: And now you know why Al's a "shingle" man, jokes like that.
Al: In order to demonstrate how these cables melt the snow, we'd have to spend hours installing the coils.
Tim: We'd also have to make it snow in the building.
Al: Hm. And that hasn't happened since Tim blew a hole in the roof.