WARREN — The National Weather Service is investigating a severe storm in northwestern Pennsylvania that downed trees and may have spawned a small tornado.

The storm hit parts of Erie, Crawford and Warren counties Sunday evening.

No injuries were immediately reported, but Warren County Public Safety Director Todd Lake says hundreds of people were left without power for a time.

Lake says he’s asking the weather service to investigate because some of the downed trees are “crisscrossed,” a sign of tornadic activity.”