Somerset County Coroner Wallace Miller tells The Associated Press that state police are investigating the girl's death, but it is considered "weather-related."
Police have yet to release the girl's name. They say she was killed just before 7 a.m. Thursday in her Somerset Township home, about 60 miles southeast of Pittsburgh.
The girl's death comes six days after four people were killed in flash flooding caused by severe storms in Pittsburgh. Police are patrolling the section of Washington Boulevard where the people were killed, but the road remains open.
The storms are part of a front sweeping east from the Midwest.