[morio]

There are many failure points but one are the high voltage carrying power lines themselves.

As they reach their capacity they start to droop quite a bit, which in itself can cause issues like touching something they usually would not.

Because HV lines are made from aluminum they loose some of their strength as they are heated up. Above 100C or so the aluminum anneals which means strength is lost. Now you just need some wind shaking those lines and the whole thing breaks. If you have reached that point you likely have to replace the entire length of the HV line.

Of course the cold weather counters some of this. But only to a certain point.

If just one HV line fails you now have to deal with the cascading effect as the current is load balanced on the remaining HV lines.