(CNN) -- Daylight revealed evidence of widespread devastation Sunday, a day after severe flooding and tornadoes killed at least seven people and injured dozens in Missouri, Arkansas and Texas.
At least three tornadoes touched down in east Texas, leaving five people dead, Van Zandt County officials said.
The body of a 72-year-old woman was recovered in southwestern Missouri after floodwater washed away her car.
Another woman died Saturday after a tree fell on her mobile home in De Witt, Arkansas, about 80 miles east of Little Rock, according to police.
Tornadoes ripping through north Texas left widespread destruction and more than 50 people injured, officials said.
More than 30 million Americans remain under flash flood watches and warnings Sunday as the storm moves eastward. It began hitting the southwest and Midwest states Friday.
Rainfall amounts of 4-6 inches were reported in Missouri and Texas, with some areas seeing up to 9 inches, the National Weather Service said.
At least three tornadoes touched down east of Dallas as severe storms moved through the area, the weather service said.
The storm struck around 6:20 p.m. (7:30 p.m. ET) and produced extensive damage about 60 miles east of Dallas in Van Zandt and Henderson counties, according to the weather service.
Five people were found dead, but county officials said the number may go up as search and rescue efforts continue.
"We have catastrophic damage," reported J.D. Miles of CNN affiliate TV station KTVT.
He said huge tree limbs had been blown onto roads, blocking them. And vehicles on a lot were "tossed around like toys," he said.
At least 55 patients were taken to ETMC Regional Healthcare System, hospital spokeswoman Rebecca Berkley said. One was in critical condition, and the other patients' injuries were not life-threatening.
Multiple ambulances were at the site of the tornadoes while the search and rescue efforts continued, Berkley said.
First responders from across the state continue to comb through overturned cars and the homes destroyed by the tornadoes.
Canton High School was used as a triage center, CNN affiliate KLTV tweeted.
Campers and families attending First Monday Trade Days, one of the largest outdoor collectibles markets in the US, were forced to take shelter in bathrooms, CNN affiliate KLTV reported.
Preliminary reports show tornadoes touched down in several north Texas towns.
A team will survey the damage on Sunday to determine the intensity of the tornadoes.
Storms began Friday around the state, bringing heavy rain and causing flooding, the weather service said.
A couple was left stranded in their car when flood waters began to rise in Christian County, officials said.
Despite a man's efforts to rescue his wife, their car was swept away with the 72-year-old woman inside. The woman's body was found Saturday in a field near Clever, Missouri.
At least 150 roads, mostly in southern Missouri, were closed by flooding, the Missouri Department of Transportation said.
A total of 93 evacuations and 33 water rescues were reported Saturday, Gov. Eric Greitens said.
"Our standing first responders are working to protect life and property in this storm. Grateful for their work. Stay home. Stay safe," he wrote on Twitter.