BIRMINGHAM, Ala. — Severe thunderstorms crawled across the Southeast on Monday, dumping heavy rains and causing flash flooding in central Alabama, where crews in small boats and military trucks had to rescue dozens of people from their homes and cars.

In Mississippi, police and volunteers searched for a 9-year-old girl who was swept away by a flash flood after the storms dropped nearly 7 inches of rain there over the last two days. A possible tornado damaged homes and hurt seven people in another part of the state.

The storms walloped Mississippi on Sunday and spread overnight into Alabama and Georgia. Strong winds downed trees, power lines and snarled rush hour commutes.

In Pelham, just south of Birmingham, more than 4 inches of rain fell from 7 p.m. Sunday to 7 a.m. Monday. Police and firefighters rescued people who became trapped in townhomes and a mobile home park that flooded because of a nearby swollen creek.

Dozens of cars had water up to their roofs, and fast-moving water rushed by the bottoms of the mobile homes. Rescue workers wearing life jackets waded through muddy water nearly to their chests to reach stranded residents. Hundreds of more people in mobile homes on higher ground were isolated because water covered the only entrance to the complex.

Pelham Fire Battalion Chief Mike Knight said people realized at daybreak that water, 7 feet deep in some places, was surrounding their homes. Some people had to abandon cars after driving into areas where the flood water was deeper than expected.

“It’s been a long time since it’s done this, so people kind of weren’t expecting it,” he said.

At an apartment complex in the suburb of Homewood, rescue crews used a boat to help several residents and pets get out of flooded first-floor units. Mudslides toppled trees and blocked several roads.

At a stairway tread company in Pelham, about a foot of water overflowing from Buck Creek filled the inside of the small factory and swept across the American Safety Tread parking lot. Worker Terry Browning said about 50 people would normally be working.

“What they’re doing right now is getting all the power cut off, and then we’ll go home, I guess,” he said.

Some roads in Birmingham became impassable due to flood waters and fallen trees, and schools delayed opening in many areas of central Alabama due to the heavy rains.

At one point, Birmingham-based Alabama Power Co. reported 11,000 homes and businesses without electricity, but they had trimmed those outages to about 8,000 by midday.

In Augusta, Ga., where the Master’s golf tournament is being held this week at Augusta National, practice round play was temporarily suspended Monday because of severe weather.

Alabama Power Co., the state’s largest electric utility, reported 11,000 homes and businesses without power, with 6,200 in the Birmingham area.

In Mississippi, a 9-year-old girl was last seen playing in floodwater near her parents’ house around 7 p.m. Sunday in Yazoo City, the Delta region northwest of Jackson.

Authorities have not identified the girl.

Yazoo County Director of Emergency Management Joey Ward said a neighbor saw her wash into a culvert.

“She did not know how to swim,” Ward said. “We’re hoping she was trapped or caught by some of the debris and we can find her as soon as we can.”

Ward said divers have cleared all the culverts and attention turned to a large canal.

Farther south, a possible tornado damaged homes in Covington County, where seven minor injuries were reported, the Emergency Management Agency said. Wind damage was reported elsewhere.

In metro Atlanta, heavy rains slowed cars on the interstates and traffic lights were knocked out. Rain was expected to continue for much of Monday and flood warnings were in effect across the region.