A vehicle travels Tuesday in Greenville, S.C. Snow and icy conditions were expected to continue in the state through Wednesday. (Rainier Ehrhardt/AP)

A major winter storm that has caused at least six deaths unfurled across much of the South on Tuesday, and forecasters warned that potentially high accumulations of ice could cripple road travel in Atlanta and other areas in the region and result in broad power outages in the coming days.

The storm could be “a catastrophic event” of “historical proportions,” the National Weather Service office in Peachtree City, Ga., said of the latest blast of wintry weather to hit the region in recent weeks.

Conditions were expected to worsen overnight, with up to an inch of ice predicted in parts of South Carolina and Georgia.

Two to six inches of snow fell in north Georgia on Tuesday, with five to nine inches more expected by Thursday morning, said National Weather Service meteorologist Dan Darbe.

But Darbe said ice was the bigger worry, with a quarter to three-quarters of an inch expected in the area that includes metropolitan Atlanta.

The last significant ice storm in that region was in January 2000, when a quarter- to a half-inch of ice left more than 350,000 people without power, Darbe said.

President Obama signed an emergency declaration for Georgia. The governors of Alabama, North Carolina, South Carolina and Mississippi declared weather emergencies, and Georgia Gov. Nathan Deal (R) ordered state government closed Wednesday.

The storm caused two weather-related traffic deaths in Mississippi and three in northern Texas, authorities said. A Dallas firefighter responding to an accident on an icy road also died when a skidding car hit a parked vehicle and he fell off a highway bridge.

Officials were quick to make plans for dealing with the weather after being criticized for in­adequate preparation before a storm two weeks ago. The earlier rare blast of wintry weather in the region paralyzed Atlanta area roads and forced more than 11,000 students in Alabama to spend the night at their schools.

On Tuesday, hundreds of schools and offices were closed from Texas to North Carolina, and more closures were planned for Wednesday. Amtrak canceled trains in the Southeast and Mid-Atlantic states.

State transportation workers in North Carolina sprayed nearly 2 million gallons of brine on roads ahead of the storm to help keep the snow and ice from sticking, the governor’s office said.

In contrast to the storm that brought Atlanta to a standstill last month, traffic around the city was light on Tuesday as most schools and many businesses were closed in anticipation.

— Reuters