Authorities were conducting a frantic search Friday for 20 girls missing from a summer camp after ferocious floods in central Texas swamped entire communities, killing more than a dozen people.

The Kerr County Sheriff's Department confirmed at least 13 fatalities in its community about 75 miles west of Austin and authorities braced for more victims.

Rescue operations were underway in multiple communities, with a frantic search for 20 girls missing from the Camp Mystic, an all-girls summer camp where about 700 attendees were camping when torrential rains struck.

"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 told a news conference Friday afternoon.

Patrick said approximately 20 children were unaccounted for on Friday. "If they are alive and safe, we will find them and bring them home to you," he said.

The camp said in a statement, read by Patrick, there had been a "catastrophic level" of flooding and if parents had not been contacted, their child is accounted for.

Authorities said an entire month's worth of rain rushed down in central Texas, triggering warnings Thursday night and Friday morning as residents were preparing to celebrate Independence Day.

“Conditions are life-threatening! DO NOT go out onto the roads,” the local National Weather Service warned Friday morning. “Expect roads washed out and rapid rises on rivers and creeks.”

The flooding has resulted in fatalities in Kerr County, just about 75 miles west of Austin, Texas, per local officials.

“This is a catastrophic flooding event in Kerr County,” the Kerr County sheriff’s office said on Facebook. “…The entire county is an extremely active scene. Residents are encouraged to shelter in place and not attempt travel.”

Storms have brought between 4 and 6 inches—and in some locations a reported 10 inches—of torrential rainfall to the central Texas region since Thursday evening, prompting several flash flooding emergencies. 

This is a developing story.