UPDATE: 11.40 p.m. EDT - According to Lower Colorado River Authority data, the Llano River rose to 21 feet in less than an hour. The river is now at major flooding level at 22.04 feet. Floodgate operations to pass flood inflows from the river through lakes LBJ and Marble Falls will begin Tuesday morning.

Original story:

At least 4 people are missing as heavy rain washed away a recreational vehicle (RV) park in the city of Junction in West Texas on Monday, prompting rescue by boats and helicopters.

Kimble County Sheriff Hilario Cantu said so far no fatalities have been confirmed, however, the RV park is completely swept away. He added they have done at least seven swift-water rescues so far but he is not sure how many people or vehicles might have been swept away.

"The problem with the RV park, as far as getting an accounting of people and getting information, the main office was also swept away. So whatever records they had there are not accessible,” he said, Weather.com reported.

He also said state and local agencies were helping with the rescues and the city of about 2,500 people was without electricity earlier, however, power has been restored now.

Texas Game Warden Rachel Kellner confirmed four men working at the park were swept away by the floodwaters before daybreak by the South Llano River and they are conducting helicopter rescues on the river, CBS News reported.

A total of 19 people have been rescued from the area so far — 15 by boat and four by helicopter, and around 45 people evacuated from the South Llano RV Park. Two of those rescued by air were found on a tree with a family dog.  Medical emergency personnel checked the rescued persons, however, it is not clear if any of them required hospitalization.

"RVs and tents were all taken into the water. We immediately were allowed to pick out about 45 people by walking in ... and throwing them a life jacket or throw-rope, but after that, (the water) got too high. Then we had to wait on helicopters and boats,” said Rachel Kellner, public information officer for the Texas Parks & Wildlife Department, Go San Angela reported.

National Weather Service meteorologist Aaron Woodward said main the flooding is along the South Llano River, next to the RV park and radar estimate shows that up to 12 inches of rain has fallen in the locality since Sunday evening.  He added after a lull on Monday afternoon, more rain was expected late Monday night and into the overnight hours in Junction.

Heavy rain fell over a several-hour period "and it just lined up perfectly that all that fell into that river canyon and it built up and pushed a giant wall downstream,” he said, KWTX reported.