The death toll from the devastating southern tornadoes has climbed to 318. That's the most from a twister outbreak since 1932.
The National Weather Service says one of the tornadoes that killed hundreds in the South had winds of 205 mph and was the first EF-5 tornado in Mississippi since 1966. That's the highest rating given by the weather service for tornado damage.
Meteorologist Jim LaDue at the weather service's Storm Prediction Center says he expects many more of the tornados that killed at least 297 people will be rated EF-5 later Friday.
The weather service said the tornado hit Smithville, Miss., at 3:44 p.m. EDT on Wednesday. It was a half-mile wide and was on the ground for close to three miles, killing 14 and injuring 40.
The tornado destroyed 18 homes, which the weather service said were well built, less than 10 years old and bolted to their foundation.
President Barack Obama arrived in Alabama Friday, the hardest-hit of six states ravaged by a series of storms and tornadoes that killed nearly 300 people and left entire neighborhoods in ruins.
Obama was scheduled to meet with families affected by the storms as well as government officials. Shortly after Obama's arrival Friday morning, Birmingham Mayor William Bell said Obama told him that federal help will continue flowing to the devastated region.
"He assured us that he will continue to get us the resources necessary," Bell told CNN affiliate WBMA. "We're doing all we can as a local government. "We just need more assistance from the federal government."
The president's scheduled visit is taking place as emergency responders in Alabama and five other states continue to assess the damage wreaked by one of the worst outbreaks of violent weather in the southeastern United States in decades, experts said.
The severe storms and tornadoes pounded the region Wednesday and Thursday. They leveled entire neighborhoods, rendered major roads impassable and left nearly 1 million customers without power.
Alabama suffered the greatest of loss of life with at least 210 fatalities in 19 counties confirmed by the state Emergency Management Agency. The state said 36 people died in Tuscaloosa, the hardest-hit community. Heather McCollum, a city spokeswoman, said Friday that 42 people had died in that city, but those additional deaths had not yet appeared in the official state report.
The storms also left 34 people dead in Tennessee, 33 in Mississippi, 15 in Georgia, five in Virginia and one in Arkansas.
In Alabama, emergency management officials said Friday that 35 teams have been deployed to Tuscaloosa and six other counties hit hardest by the storms to assist in recovery efforts.
Officials also warned Tennessee motorists not the cross the Alabama state line without filling up their tanks first. Widespread power outages and devastation from the storms have likely rendered functioning gas stations in northern Alabama hard to find, according to a statement released by officials in both states.
The storms cut swaths of death and destruction along U.S. Highway 72 in northern Alabama and Interstate 59 from Tuscaloosa County to the northeastern corner of the state.
Maddox said at least one strong tornado swept through the city, leaving dozens of roads impassable and destroying hundreds of homes and businesses.
"It literally obliterated blocks and blocks of the city," Maddox said.
The city remained under an overnight curfew that was scheduled to expire at 6 a.m. Saturday. City officials early Friday also advised Tuscaloosa residents who live south of the Black Warrior River and east of McFarland Boulevard to boil their tap water.
Obama had signed a disaster declaration for Alabama, which enables storm victims and damaged businesses in eight counties to seek federal aid.
The University of Alabama in Tuscaloosa escaped mostly unscathed, but two students died.
In the Alabama town of Rainsville, 25 bodies were recovered near a trailer park, said Police Chief Charles Centers. Many people are unaccounted for, he said.
"People's lives have just been turned upside down," Alabama Gov. Robert Bentley said during an appearance in Tuscaloosa. "It affects me emotionally. When I fly over this, it is difficult."
On Friday, the National Weather Service said the tornado that struck Smithville, Mississippi, killing 14 people on Wednesday, was a rare EF-5 storm with peak winds of 205 mph. The last such tornado recorded in the United States struck May 25, 2008 in Parkersburg, Iowa.
The tornado, the Weather Service said, destroyed 18 homes, a post office, a police station and a water treatment system. In addition to the 14 deaths, it caused 40 injuries, the Weather Service said.
The storms are being compared to the "super outbreak" of tornadoes on April 3 and 4, 1974, Craig Fugate, the FEMA administrator, said Thursday.