Dallas, Texas (CNN) -- At least four tornadoes spawned by Tropical Depression Hermine touched down in and around Dallas, Texas, on Wednesday evening, knocking down walls and smashing vehicles.
Sirens went off in downtown Dallas as one funnel cloud was spotted in Cockrell Hill southwest of downtown, according to CNN affiliate WFAA.
One tornado was reported in Ellis County and three in Dallas County, according to CNN meteorologist Taylor Ward.
Aerial footage from the area showed buildings in an industrial complex with walls knocked down and roofs blown off. The roof of a tractor-trailer truck in a parking lot was caved in by cement blocks blown from a nearby building.
A spokesman for the Dallas Fire Department said Wednesday night that damage seemed to be isolated to a warehouse district on Mockingbird Lane in the western part of the city.
There was one serious injury, Jason Evans of the fire department said. A truck driver's rig was picked up by the tornado, spun around and slammed into a warehouse. The driver was sitting in the cab of the truck when the front of the building collapsed on the truck.
Further information on the driver and his injuries was not immediately available.
Operations at Dallas' Love Field airport were shut down temporarily as a tornado approached the field, according to Lynn Lunsford of the Federal Aviation Administration. Tower personnel were preparing to evacuate when the tornado turned away at the last minute, Lunsford said.
"Tornadoes are a common phenomenon on the eastern side of landfalling tropical systems due to increased turning of the winds with height or vertical wind shear," Ward said.
Rescue workers across central and north Texas, meanwhile, plucked people stranded by fast-rising floodwater dumped by Hermine as it slogged northward.
At least one motorist in Austin was missing.
Texas Gov. Rick Perry directed the activation of state search-and-rescue capabilities, bringing in swift-water rescue teams, UH-60 Blackhawk helicopters and other resources.
"I urge all Texans to realize the dangers of crossing flooded roadways and respect the barricades put in place by officials to protect Texans' lives," Perry said in a written statement.
Forecasters had said most parts of central and eastern Texas and Oklahoma could receive 4 to 6 inches of rain, but the numbers for some parts of Texas were staggering.
Before the bulk of the storm moved out of Texas, Georgetown had received 13.2 inches of rain Wednesday, according to the National Oceanic and Atmospheric Administration's Hydrometeorological Center. Cedar Park had received 12.9 inches; Anderson Mill, 12.7 inches; Killeen, 11.6 inches; and Austin, 11.4 inches. Fort Worth had recorded 6.8 inches of rain, San Antonio, 6.7 inches and Houston, 4.4 inches.
Aerial images showed scores of flooded streets and some rescues in Dallas.
Portions of Austin had endured 15 inches of rain, and a middle-age motorist was missing after her car was washed away, Emergency Management spokeswoman Reyne Telles said. The car was found.
Thirty-two roads were closed, and an engineer from the watershed department said this could be a 250-year event, Telles told CNN.
"I haven't seen anything like this happen here before," said an employee at a County Line BBQ location near Bull Creek. "One of the boat docks washed away, and there are boats and cars stranded in the river." The restaurant was closed Wednesday but may reopen Thursday. The employee asked not to be identified.
As of 5 p.m. ET, Hermine was about 135 miles (215 kilometers) southwest of Oklahoma City. It had maximum sustained winds of 25 mph (40 kph) and was moving at 12 mph (19 kph).
By late afternoon, radar showed the rain was centered on eastern Oklahoma, with a line extending down to the Mexican border in eastern Texas.
"Additional rainfall amounts of 3 to 6 Inches with localized higher amounts can be expected through Thursday from eastern Texas and Oklahoma into Missouri and Arkansas," the National Hurricane Center said. Flash flood or flood warnings were in effect for much of those states.
Meanwhile, newly formed Tropical Storm Igor was bringing "squally" weather to the Cape Verde Islands on Wednesday, the National Hurricane Center said.
As of 4 p.m. ET, the center of Igor was about 75 miles (120 kilometers) south-southwest of Praia in the Cape Verde Islands. It had maximum sustained winds of 45 mph (72 kph) and was moving west at 6 mph (9 kph). The storm is expected to slowly strengthen over the next 48 hours, with a slight turn to the west-northwest and an increase in forward speed.
A tropical storm watch was in effect for the southern Cape Verde Islands, including Maio, Sao Tiago, Fogo and Brava. Tropical storm conditions were possible in those locations in 12 to 24 hours, forecasters said.
Tropical storm-force winds extended about 50 miles from Igor's center.
Forecast maps show Igor becoming a Category 2 hurricane early next week over the open Atlantic.
CNN's Sean Morris contributed to this report.