I did the math and figured out that according to the laws of physics, for any specific type of wire between poles a given distance apart, the more slack the wire has, the less its weight between those two poles gets magnified into tension force. When there's a buildup of ice on the wire and the wire has very little slack, the weight of the ice is already a lot heavier than the wire but the weight of the ice also gets greatly magnified into a force of tension that's much bigger than the weight of the ice on the part between those two poles. My question is
Did most of the places where part of a power line that fell down during a freezing rain storm fell down only from the weight of the ice on the power lines and not from a tree branch that fell down from a buildup of ice on it bringing down a power line with it? If so, did most of the spots where part of a power line fell down only from the weight of the ice on it have very little slack?
If so, this fact might be so useful for research. Maybe in the future, power lines could be built with more slack to account for the possibility that so much ice might build up on them during a freezing rain storm.