The tree came down around 9:00 p.m. Tuesday along Montgomery Avenue, between Woodside Avenue and Anderson Road in Ardmore, Pa, during a storm.
The tree damaged seven wires and seven utility poles, Peco said.
The damage knocked out power to some 550 Peco customer, but work was well underway to restoring them all on Wednesday.
The tree used to sit in Kate Croce's back yard. She said she heard a loud bang and rushed outside.
A neighbor told her what happened.
"He said 'A tree on your property fell down.' I said 'One of my trees?!"
The road remained closed on Wednesday evening, so commuters were urged to find alternate routes.
The mess snarled traffic all morning long. Montgomery Avenue was bumper-to-bumper, and Lancaster wasn't much better. "It probably took me 45 minutes to get from Bryn Mawr to here," said Holly Stone of Bryn Mawr. "It is a pain in the neck, but it's always better to know why," said Andrew Douglas of Fort Washington. "It was Mother Nature - hard to argue with that."