(CNN) -- Parts of Alabama and much of Mississippi were under flood warnings Wednesday night, as rivers throughout the region rose after a day of storms and torrential rain.
Rivers in western Alabama, including the Tombigbee and Black Warrior rivers, are either above flood stage or expected to top that level in a matter of hours, according to the National Weather Service. The agency does not expect water levels to begin receding until the weekend.
The situation is similar across Mississippi and almost the entire state is under a flood warning, according to the agency. Multiple rivers and creeks are already past their flood stages, or the agency believes they will be soon based on previous rainfall amounts and the amount expected in the next few hours.
Even the Mississippi River near Natchez is expected to go above flood-stage some time Thursday morning.
A band of intense thunderstorms pushing eastward Wednesday afternoon after leaving a patchwork of destruction in the Deep South from rain, lightning, high wind and tornadoes.
The storm spawned at least two confirmed tornadoes in Mississippi early Wednesday, and lightning from the storm is believed to have caused a house fire in Yazoo County that killed a 69-year-old woman and injured her husband, CNN affiliate WAPT in Jackson reported.
Damage in the towns of Terry and Utica was caused by tornadoes that struck less than 30 minutes apart early Wednesday, a National Weather Service survey crew told WAPT. The tornado in Terry was rated an EF-2 on the Enhanced Fujita Scale, with winds of 115 mph. It uprooted trees and damaged several homes.
Homeowner Michael Bankston told CNN affiliate WAPT in Jackson that he had gotten out of bed to get a drink of water at a little after 1 a.m. when the twister hit.
"It didn't take but a couple seconds," he told the station. "When I started hearing the windows blow out, that I knew something major was going on."
The second twister, an EF1 with maximum winds of 95 mph, struck in Utica less than a half-hour later, knocking a home off its blocks and damaging other structures.
Theodore, Alabama, got the brunt of the most dramatic weather Wednesday morning, when an apparent tornado caused extensive damage to several businesses in the Mobile suburb. Four people received minor injuries.
It was "30 seconds of pure hell," said a man who witnessed the scene as the storm tore into a BP gas station. The station's awning collapsed, the roof was ripped off and trucks were flipped over, he told CNN affiliate WALA in Mobile.
One bystander said he saw a funnel cloud forming and went to find shelter. A Church's Fried Chicken restaurant and a grocery store were next to be struck.
"I'd been through some weather ... but nothing like that," Larry Bosarge told WALA. "It was loud and we had just enough time to take cover."
About a quarter-mile down the road, a strip mall and a residence received extensive damage. Police said 15 vehicles that were too damaged to operate had to be towed away.
CNN correspondent Stephanie Oswald said the power lines between the gas station, restaurant and grocery store were still intact, suggesting that the presumed tornado hopped from one building to the next. She described the scene as a good half-mile of structural damage.
It was "a miracle nobody got killed," Mobile Police Capt. Jack Dove told CNN.
Wednesday afternoon, Alabama Gov. Robert Bentley declared a statewide state of emergency in response to damage from the storms, authorizing the Alabama Emergency Management Agency to assist communities, make the appropriate assessments of damage and seek state and federal assistance for the affected areas, according to a news release from the governor's office.
In Mississippi, preliminary reports of damage from 19 counties included many roads affected by flooding and debris, homes damaged by high winds and fallen trees.
Much of the region had already been saturated by rainstorms over the weekend, leaving large trees vulnerable to winds that at times gusted in the tropical storm force range.
Residents of Stone County, Mississippi, were clearing away damage from uprooted trees and power poles after gusts of 40-50 mph tore through the area Wednesday morning, according to CNN affiliate WLOX in Biloxi.
And in southwest Atlanta, a large oak fell and blocked the front door of homeowner Hallie Hill, who told CNN affiliate WSB that the tree "just fell real easy." It knocked out power lines and left a 2- to 3-foot hole in the street, WSB reported.
The storm ripped the roofs off two buildings at the Anchorage, an addiction rehabilitation center in southwest Georgia, and left water damage in several buildings, executive director Kenny Phillips told CNN affiliate WALB in Albany.
A CNN iReporter at Pensacola Naval Air Station in the Florida Panhandle said "a green hue to the sky" preceded a tornado warning siren and a torrential downpour with lightning and thunder, but he didn't see a tornado.
"Everyone had to stay on base," said the iReporter, who asked to remain anonymous. He said he and about eight other people took shelter in the barracks, "laughing at the people that had to run through puddles."
As the brunt of the storm moved out of Louisiana, it left behind swollen rivers and flooded streets from heavy rains that started just as Mardi Gras ended. CNN affiliate WGNO in Metairie, Louisiana, showed motorists gingerly trying to navigate through a foot of water on a busy street Wednesday morning.
Flood watches were in effect in much of Appalachia, and the heavy rain is expected to push into the mid-Atlantic and Northeast regions Thursday.
CNN's Cameron Tankersley, Joe Sterling and Maria White, and correspondent Stephanie Oswald in Theodore, Alabama, contributed to this report.