(The Center Square) — At least 13 people are dead and 20 girls are missing amid flash flooding in Texas Hill Country, state and local officials said.

Search and rescue operations are ongoing throughout the region, including for 20 girls who were attending a summer camp during the flash flooding.

“Within 45 minutes, the Guadalupe River rose 26 feet and it was a destructive flood – taking property and, sadly, lives,” Texas Lt. Gov. Dan Patrick said at a Friday news conference.

Reports of over a foot of rain hitting the region overnight and into the morning Friday have led to “catastrophic flooding,” according to the Kerr County Sheriff’s Office, which confirmed at least 13 were dead. Officials are still trying to identify the identities of the victims, the Sheriff’s Office said.

Flash flood emergencies were declared throughout the region including Kerr, Tom Green, and Kendall Counties, with the city of Kerrville issuing a disaster declaration.

The Guadalupe River carried a “deadly flood wave,” according to the National Weather Service, which urged residents in its path to seek higher ground as quickly as possible.

Meanwhile, people are being asked to shelter in place while search and rescue missions continue. With roads too dangerous to drive, those in need of evacuation have been asked to call local law enforcement.

The Kerr County Sheriff’s Office said, “The entire county is an extremely active scene. We can confirm fatalities but will not release further information until next of kin are notified.”