As the storm advanced up the Eastern Seaboard, it left customers in Louisiana, Arkansas, Texas, Mississippi, Alabama and the Carolinas without power, NBC News reported.
Deserted Atlanta streets were slick with ice and described as a ghost town. The Atlanta area and other parts of Georgia prepared for the storm the National Weather Service warned could reach "historic proportions," with forecasts of more than an inch of ice weighing down power lines and turning roads into skating rinks, the Wall Street Journal reported.
In a video posted on the city's website, Atlanta Mayor Kasim Reed urged people not to leave their homes for the next 48 hours if possible.
"I want you to be safe, and I want you to stay at home," he said.
Brian Green of the utility company Georgia Power said 8,000 of its employees and support personnel were ready to repair power lines downed by the storm and deal with related issues.
The weather service referred to the storm as a "catastrophic event" and urged Georgians to "be prepared to be without power in some locations for days and perhaps as long as a week."
By midafternoon Wednesday, more than 3,000 flights across the United States had been canceled and 3,198 delayed, more than 2,000 of them at Atlanta's Hartsfield-Jackson hub, NBC News reported.
The mountainous regions of Georgia near North Carolina and Tennessee prepared for up to 9 inches of snow and howling winds, forecasters said.
At least six deaths were blamed on the storm Tuesday as it gathered strength over Texas and Mississippi.
Four people were killed in separate accidents on icy north Texas roads, including a Dallas firefighter responding to an accident who was knocked off a highway overpass, KXAS-TV, Dallas, reported. Two people were killed in separate accidents in Mississippi, the state Highway Patrol said.
A weather-related accident Wednesday morning, involving an 18-wheeler truck, injured three people and led to the spill of the hazardous chemical isopropyl 2-chloroprioponate onto a bridge over the Mississippi River near Vicksburg, Miss. The spill closed Interstate 20 and detoured cars in the area, the (Jacksonville, Miss.) Clarion-Ledger reported.
Governors of Louisiana, Mississippi, Alabama, the Carolinas and Maryland declared weather emergencies. Georgia Gov. Nathan Deal signed an executive order closing all state government offices Wednesday.
Schools, universities, offices and government buildings were closed from the Southwest to the Southeast coast.
Further north, the weather service raised its prediction for heavy snow in New York, issuing a winter storm warning Wednesday that said accumulations of between 10 and 14 inches of snow were possible in the New York area by Friday.
Amtrak suspended some rail service from New York and south of Washington Wednesday because of the weather. Amtrak officials said some trains also would be suspended in Georgia, Florida and the Carolinas.
"This is one of Mother Nature's worst kinds of storms that can be inflicted on the South," Deal said Tuesday. "Ice -- that is our biggest enemy."
Deal and Reed were roundly criticized for their response to a Jan. 28 storm system that left thousands of people stranded in traffic jams caused by icy roads, accidents and congestion throughout the Atlanta area.
The storm is forecast to move up the East Coast from Wednesday into Thursday, dumping heavy snow from Virginia to New England.