Tuscaloosa Mayor Walter Maddox asked people Thursday to stay off the streets and conserve water, and for gawkers to stay away. He said "sightseers" are only getting in the way of emergency crews.
"This is going to be a very, very long process" of cleaning up and rebuilding, he said. "During this time we ask for patience and we ask for prayers."
Also hit hard by the twisters was the town of Smithfield, Miss. At least 32 fatalities were reported killed statewide.
"I think the only word that accurately describes anywhere near what's happened, here, is devastation," U.S. Rep. Alan Nunnelee, R-Miss., said.
Nunnelee said federal help is also on the way for survivors and victims.
"We want to make sure that we get every bit of assistance that is available anywhere in the nation; make sure that it's available to north Mississippi.
ABC News Radio, Michael S. James, Mike Marusarz, Jessica Hopper and the Associated Press contributed to this report.