Blizzard conditions and flash flood warnings hit the already-ravaged residents of the heartland Monday after a string of severe storms left at least 43 people dead across seven states during the previous four days.

Parts of 11 states were under a winter storm warning Monday morning as the weather system that spawned tornadoes in Texas and flooding in Missouri moved on.

The National Weather Service issued flash flood warnings for southern and eastern parts of Missouri, including St. Louis, and a small section of northern Arkansas. Most of Arkansas, eastern Oklahoma, central Missouri and central Illinois were under a flood warning. Authorities said more than 180 Missouri roads and several bridges in the state were closed following heavy rainfall during the weekend, and more expected Monday.

Forecasters said Iowa, Wisconsin, Michigan and parts of Minnesota, Illinois, Missouri, South Dakota, Nebraska, Kansas, Oklahoma and Texas would see winter weather conditions ranging from heavy snow to ice, accompanied by gusty winds.

Parts of the Southeast would see rain, while more severe weather was possible in Mississippi.

The gloomy forecasts came as residents of the Dallas area began to assess the damage from Saturday's string of at least nine tornadoes that swept through the region, killing at least 11 people.

Local officials estimated as many as 1,450 homes were damaged or destroyed. Vehicles were mangled, power lines fell and trees were toppled. Heavy rain, wind and falling temperatures hampered cleanup efforts Sunday afternoon.

"This is a huge impact on our community, and we're all suffering," Garland Police Lt. Pedro Barineau said of the suburb about 20 miles northeast of Dallas, where eight people died, 15 were injured and about 600 structures, mostly single-family homes, were damaged.

The National Weather Service said an EF-4 tornado, which is the second-most powerful with winds up to more than 200 mph, hit the community at about 6:45 p.m. Saturday. It was near the intersection of Interstate 30 and George Bush Turnpike, which is a major route in the region. At least three people who died were found in vehicles, said Barineau, who also noted that some cars appeared to be thrown from the interstate, though it wasn't known whether that was how the people found in the vehicles died.

Barineu described the scene in the town to the Dallas Morning News as "total devastation."

The destruction in Garland was so overwhelming that Dallas County Judge Clay Jenkins declared the city a disaster within mere minutes of seeing the toll firsthand.

"I don't declare local disasters lightly," Jenkins said. "But I looked at the scene for 10 minutes, spoke to the incident commander and then called the lawyers to bring the paperwork."

In the nearby town of Rowlett, City Manager Brian Funderburk said Sunday morning that 23 people were injured, but that there were no deaths and no reports of missing people. The weather service said damage indicated it was likely an EF-3 tornado, which has winds up to 165 mph.

Jenkins said in a statement Sunday night that as many as 600 homes were damaged in Rowlett.

Three other people died in Collin County, about 45 miles northeast of Dallas, according to sheriff's deputy Chris Havey, although the circumstances were not immediately clear.

Texas Gov. Greg Abbott made disaster declarations Sunday for four counties — Dallas, Collin, Rockwall and Ellis — and warned that the number of victims could rise.

Meanwhile, Oklahoma Gov. Mary Fallin declared a state of emergency as there were blizzard conditions and an ice storm warning out west and flood warnings in the east, where one community had received 9 inches of rain. The state Department of Emergency Management said eight storm-related injuries were reported. About 60,000 homes and businesses were without power.

In neighboring Arkansas, officials said it appeared that a tornado touched down in Bearden, tearing roofs off buildings and uprooting trees. There were no immediate reports of injuries.

Further north, rain caused dangerous driving conditions and flooding in Missouri, where Gov. Jay Nixon also declared a state of emergency, and Illinois.

Six people died overnight when two separate vehicles drove into flooded roadways in south-central Missouri, Pulaski County Sheriff Ronald Long said. Among them were four international soldiers based at Fort Leonard Wood, he said. Greene County authorities said two fatalities there were associated with the flooding.

In southern Illinois, authorities said three adults and two children drowned Saturday evening when the vehicle they were riding in was swept away and sank in a rain-swollen creek.

The death toll in the Southeast linked to severe weather rose to 19 on Sunday when Alabama authorities found the body of a 22-year-old man whose vehicle was swept away while attempting to cross a bridge; a 5-year-old's body was recovered for that incident Saturday. Ten people have died in Mississippi, and six died in Tennessee. One person was killed in Arkansas.

The Associated Press contributed to this report.