(CNN) -- Severe flooding killed at least five people in central Tennessee on Saturday, officials said, as floodwaters inundated roads, highways and homes in and around the Nashville area.
The National Weather Service also said 33 of 75 counties in Arkansas are under a tornado warning, and 25 counties in Tennessee are under a tornado watch.
Two people were killed Saturday when floodwaters swept them away as they tried to seek safety on the roof of their SUV about 80 miles northwest of Nashville, Stewart County emergency management spokesman Clint Mathis said.
Three more people were reported dead in counties near Nashville, Tennessee Emergency Management spokesman Jeremy Heidt told CNN.
Between 6 and 10 inches of rain has fallen in 12 hours in the area, causing "extremely dangerous" flooding, the National Weather Service said.
"This is one of the most severe rain events Nashville has ever experienced," Nashville Mayor Karl Dean said in a statement.
Dean said more than 50 water rescues had been conducted Saturday, and more were under way.
"I urge all Nashville residents to stay home and stay off the roads," Dean said.
At least 2,000 people were displaced after two levees broke in Millington, a small city near Memphis, Millington Police said.
Video from CNN affiliate WZTV showed more than a dozen vehicles submerged in several feet of swift-moving water on I-24 in Nashville.
Rescue workers helped drivers escape as water surrounded their cars, CNN affiliate WSMV reported. The floodwaters pushed a home off of its foundation and into the middle of I-24.
Video from WZTV showed a school annex building floating down the interstate before breaking into pieces.
Officials are advising residents to stay off roads, as many have become impassable.
Janel Lacy, a spokeswoman for the Nashville mayor's office, said that in addition to I-24 in Davidson County, 20 other local roads were closed.
CNN iReporter Andrew Ellis sent in a video of a "raging river" of water rushing over an open field where people usually play soccer and golf in Lexington, Tennessee.
"The flooding brought the town to a standstill. No one could get in and no one could get out," he said. "Many homes, vehicles and entire neighborhoods either were or still are under water."
CNN iReporter Jennifer Alter said her dad helped her push her car out after she got stuck on Christmasville Road in Jackson, Tennessee, on the way to work early Saturday morning.
"We went back to check it a few hours later and the road was gone," she said.
Lacy said one shelter had opened at Lipscomb University, and officials planned to open others.
The rain is expected to continue into Sunday morning, she said.
Heidt said floodwaters were expected to crest around 11 p.m. CT (midnight ET) Saturday.
The weather service has reported record flooding at Mill Creek, near Antioch, Tennessee.
CNN's Jacqui Jeras and Greg Morrison contributed to this report.