Watch: Timelapse video shows floodwaters rising rapidly in Texas' Llano River

At least 90 people have died in the catastrophic flash floods that hit Texas over the Fourth of July holiday weekend, including 27 children and counselors at beloved all-girls Camp Mystic. Dozens of people were known to be missing across the state and areas affected by the flooding, Texas Gov. Greg Abbott said at a news conference July 6, adding search and rescue efforts were still underway.

Extreme flooding began in the Texas Hill Country around 4 a.m. on July 4, as thunderstorms dropped more than 10 inches of rain on the region. The rain overwhelmed the Guadalupe River, causing it to quickly rise and surge over 26 feet in less than an hour on July 4, said Texas Lt. Gov. Dan Patrick. The hardest-hit area is Kerr County.

Timelapse footage captured by an eyewitness shows floodwaters from the nearby Llano River rising over a causeway in Kingsland, about 65 miles north of Austin, completely submerging it in just a few minutes. The video was captured around 6 p.m. CST June 4 over 50 minutes by a resident Robert Ivey.

"It really only took a few minutes to shut down the roadway," Ivey said. Watch the video at the top of the story.

The water in the river had subsided slightly as of Monday morning, Ivey told USA TODAY on Monday, July 7.

Texas devastated by flash flooding

The Llano, a spring-fed stream, is formed in Kimble County by the meeting of the North and South Llano Rivers, according to Texas Parks and Wildlife. The main stream flows east through Kimble, Mason, and Llano Counties for approximately 100 miles before joining the Colorado River and forming Lake Lyndon B. Johnson, a reservoir on the Colorado River in the Texas Hill Country about 45 miles northwest of Austin.

As search and rescue efforts are underway, more downpours and flash flooding are expected in the region and the National Weather Service extended a flood watch July 7 through 7 p.m. local time for much of central Texas, anticipating that slow-moving thunderstorms will drop heavy rain across the region.

Texas Hill Country is no stranger to extreme flooding. In the rugged, rolling terrain it’s known for, heavy rains collect quickly in its shallow streams and rivers that can burst into torrents causing flash floods. The Guadalupe has flooded more than a dozen times since 1978, according to the U.S. Geological Survey, but the Independence Day flood is among the worst in its history. 

This story was updated to fix a typo.

Contributing: Karissa Waddick, Dinah Voyles Pulver, Christopher Cann, USA TODAY

Saman Shafiq is a trending news reporter for USA TODAY. Reach her at [email protected] and follow her on X and Instagram @saman_shafiq7.