Houston residents said the wind sounded like a freight train.
At least four people were killed Thursday evening when an “extraordinarily” strong storm ripped through Houston, Mayor John Whitmire said.
Officials said fallen trees appeared to be the cause of at least two of the deaths.
The winds – which reached speeds of 78 miles per hour – sounded like a freight train, Houstonians told ABC News.
The winds were so strong that the mayor said they were comparable to Hurricane Ike in 2008.
Schools in Houston are closed Friday and more than 770,000 customers across the state are without power.
Whitmire urged residents Friday to stay home, pointing out that 2,500 traffic lights are not working.
The mayor said Houston is in “recovery mode.”
“Please…stay away from the city center – it’s dangerous. There’s broken glass in every direction,” Whitmire said.
The strong winds came after a rare “high risk” flash flood warning was issued in Texas and Louisiana, with the states bracing for up to 9 inches of rain in 24 hours.
“In the last two weeks alone, the high-risk area received over 600% of normal rainfall,” the National Oceanic and Atmospheric Administration warned, and the flash flooding could be life-threatening.
According to the Weather Prediction Center, “high risk” days account for just 4% of days but account for more than a third of flood deaths.
The storm in Houston is now over, allowing residents to begin cleanup efforts on Friday.
The severe weather threat has now shifted east, with damaging winds and large hail possible from Louisiana to Georgia.
ABC News’ Mireya Villarreal and Daniel Amarante contributed to this report.