Dawn DiIenno of Mill Creek said she heard a huge crack Saturday night and saw a light that lit up the whole house. She ran upstairs to make sure her roof wasn't on fire.
"I knew just by the sound something was on fire," DiIenno said. "I have never heard that before."
The National Weather Service said lightning struck the area of Arundel Apartments at 7:45 p.m. More than 100 firefighters and emergency personnel responded after a second-alarm was called when the first units arrived, said John Stewart, spokesman of the Mill Creek Fire Company.
The roof and third-story of the apartment building endured most of the fire damage, Stewart said.
Residents in the building where the fire occurred said they saw smoke coming from the light fixtures.