An Illinois woman was struck by lightning at the Country Thunder Music Festival in Wisconsin early Friday, officials said.

Authorities responded to a call of a medical emergency at the festival campgrounds, located in Twin Lakes, Wisconsin, at around 12:36 a.m., the Kenosha County Sheriff's Department said in a statement.

Upon arrival, officers found a woman unconscious but still breathing after being struck by lightning, authorities said.

Later identified as 22-year-old Brittney N. Prehn, from Illinois, the victim was taken to a hospital in Illinois in serious condition, according to the sheriff's office.

"I just heard a huge lightning bolt," witness Robert Kruse, of Illinois, told NBC affiliate WTMJ. "Me and a friend walked out and every cop rushed over there. Her shoe exploded off, her other shoe was all black and burnt. She had blood coming from her ears."

Further details were not immediately available. A spokesman for the Country Thunder Music Festival, which runs through Sunday, did not immediately respond to request for comment.