(ABCNews) -- More than 100,000 customers are without power in Georgia as a massive ice storm barrels through the region, slowing traffic, grounding flights, and shuttering schools and businesses.
The storm churning its way up the East Coast is expected to dump up to a foot of snow on parts of the South, a region ill-prepared for such conditions. Meteorologists are predicting that Atlanta, the region's commercial and travel hub, could be covered in up to a half inch of ice.
Nearly 75,000 Atlanta residents are without power, according to Georgia Power and another 43,000 lost power in Augusta.
Thousands of flights were grounded and emergency declarations were issued in Georgia, North Carolina, South Carolina, Virginia, Alabama, Mississippi and Louisiana ahead of the storm.
Elected leaders and emergency management officials began warning people to stay off the roads, especially after two inches of snowfall caused an icy gridlock two weeks ago and left thousands stranded in vehicles overnight. It seemed many in the region around the state's capital obliged as streets and highways were uncharacteristically unclogged.
Georgia Gov. Nathan Deal and Atlanta Mayor Kasim Reed, during a news conference at the Georgia Emergency Management Agency's special operations center Tuesday evening, implored people to get somewhere safe and stay there.
"The message I really want to share is, as of midnight tonight, wherever you are, you need to plan on staying there for a while," Reed said. "The bottom line is that all of the information that we have right now suggests that we are facing an icing event that is very unusual for the metropolitan region and the state of Georgia."
The forecast drew comparisons to an ice storm in the Atlanta area in 2000 that left more than 500,000 homes and businesses without power and an epic storm in 1973 that caused an estimated 200,000 outages for several days. In 2000, damage estimates topped $35 million.
A National Weather Service memo issued today called the storm "an event of historical proportions," identifying it as "catastrophic ... crippling ... paralyzing ... choose your adjective."
More than 200 utility vehicles from surrounding states -- including Florida and North Carolina -- gathered in a parking lot near one of the grandstands at Atlanta Motor Speedway, prepared to help, as needed.
"It's certainly going to be a challenge for us. Ice is definitely different than snow," state Transportation Commissioner Keith Golden said.
Atlanta has a painful past of being ill-equipped to deal with snowy weather. Despite officials' promises after a crippling ice storm in 2011, the Jan. 28 storm proved they still had many kinks to work out.
Like state and local officials, many commuters learned their lessons from that storm.
"Last time, I was totally unprepared. I was completely blindsided," said Lisa Nadir, of Acworth, Ga., who sat in traffic for 13 hours and then spent the night in her car when the storm hit Jan. 28. "I'm going to be prepared from now on for the rest of my life."
Nadir was telecommuting from home starting Tuesday and she had kitty litter in her trunk in case she needed to put it down on icy roads for extra traction.
Around the Deep South, slick roads were causing problems. In North Texas, at least four people died in traffic accidents on icy roads –- including a Dallas firefighter who was killed when a car, sliding on the ice, knocked him off an overpass while he was trying to help a fellow driver, authorities said.
While officials remained worried about the South, the Northeast was expected to get slammed, too. Winter storm warnings expanded to include Philadelphia and New York City this morning, with those warnings lasting from midnight Thursday until 6 a.m. Friday.
The storm was expected to intensify and move up the East Coast today into tonight, with snow forecast to fall in Washington, D.C., and New York City overnight, leading to a slow, cold morning commute for the Northeast.