Scraping ice off of power lines - GIF

[CharlesWaugh]

I think it's the sudden rebound when a long section warms up enough for it all drop at once.
KInda like dry-firing a bow with no arrow - lots of energy release and it's concentrated in the power line as a tensile member.

But . . .

I WAS WRONG! It IS weight!
Here's an article from the actual power folks:
https://www.tdworld.com/overhead-tra...age-powerlines