ATLANTA (CNN) -- The message in portions of Alabama, Georgia and the Carolinas as an ice storm swept through Wednesday was simple: Get off the roads, and stay off.
The warnings came as freezing rain brought heavy ice accumulations from Atlanta to Charlotte, where some of the Southeast's most populous cities were at a standstill. Hundreds of thousands were without power, and thousands of flights were canceled.
Calling ice the biggest enemy of the South, Georgia Gov. Nathan Deal ordered schools canceled and government offices shuttered in an attempt to avoid a repeat of a storm last month that paralyzed the city.
Up to three-quarters of an inch of ice was expected to accumulate in Atlanta and up to 10 inches of snow and sleet in Charlotte, making travel treacherous.
While most of the major thoroughfares in and out of the city of Atlanta were reportedly devoid of traffic, a different scene was playing out to the northeast where the storm moved in faster than expected.
"Stay home, if you can," North Carolina's Department of Public Safety said in posts on Twitter. "Quickly deteriorating road conditions, numerous car accidents in Durham/Franklin/Johnston/Wake counties."
For some, there just wasn't enough time.
Michael Crosswhite, 44, planned on leaving work in Raleigh, in Wake County, by midafternoon, well ahead of when forecasters initially predicted a snow and ice storm to hit the area.
But by noon, the snow and icy rain was coming down.
'Nothing you can do but hope you don't get stuck'
"We just passed an 18-wheeler that spun out into a ditch," he said by telephone more than two hours into his journey home to Durham, a trip that typically takes less than 30 minutes.
Moments later, a car ahead of him spun out in front of him.
"It's kind of slushy, and there are just icy spots that there is nothing you can do but hope you don't get stuck," Crosswhite said.
With the impression the storm would hit Raleigh later in the day, Deanna Hunt ran out to an appointment. By the time she left, it was "snow chaos."
Four hours later, she was still trying to get home. "It just came down so fast and so furious," she said on CNN's "The Situation Room."
In Atlanta, a city shut down by 2.6 inches of snow two weeks ago, it appeared the thousands of commuters, some of whom had spent up to 20 hours stuck on highways then, had learned their lessons.
Deal applauded Atlantans who kept the roads clear, saying during a midday news conference, "That's a good starting point."
Even so, there were thousands without power across the state after ice caused tree limbs to snap, knocking out power lines.
With temperatures below freezing, the National Guard opened up 35 armories across the state to be used as shelters and warming centers, CNN affiliate WSB-TV reported.
The Red Cross, meanwhile, reported more than hundreds sought shelter overnight at its facilities stretching from Louisiana to North Carolina.
In North Carolina, Kim Martin Rehberg's typical 25-minute commute was turning into an hours long ordeal Wednesday as she tried to make it from her office in Durham to her home in Raleigh.
Three hours later, she still had miles to go. So, too, did the rest of her family who were stuck in traffic across the region.
"My daughter was stranded trying to get from her gymnastics class in Apex. My ex-husband is trying to her and he got trapped," she said by telephone, referring to a Raleigh suburb.
"My husband is in Charlotte and says things are bad. All the gas stations are shutting down, and I had trouble trying to gas up."
'Our own trucks are stuck'
There are snowplows on the roads but "unfortunately some of our own trucks are stuck in the same traffic jams that a lot of other people are and they're having a hard time getting to the roads that need to be cleared," said Dan Howe, Raleigh's assistant city manager.
Stephanie Mouzon, who was one of the lucky ones. She made it to her home in Garner, North Carolina, after more than two hours.
Now the 48-year-old plans to hunker down at her home and ride out the storm.
"When I got here, I was like 'Thank you, Jesus,'" she said. "I'm not going anywhere now."
The low-pressure weather system bringing the snow and ice to the Southeast is expected to move up the East Coast, dropping snow on the Northeast. Six to 8 inches are predicted for Washington, with especially heavy snowfall Thursday morning, and 6 to 10 inches on New York from midnight Wednesday into Thursday, with a combination of snow, sleet and rain continuing until Friday morning.
New York Gov. Andrew M. Cuomo told state agencies to prepare "for an impending nor'easter" and asked residents to avoid unnecessary travel.
National Weather Service forecasters say the storm -- packed with sleet, snow, rain and ice -- is a potentially "catastrophic event."
In Georgia, more than 400 members of the National Guard were deployed for weather duty, and about 100 each for the Carolinas and Alabama.
The storm has led the Red Cross to cancel more than 1,000 blood drives, resulting in a shortage. Anyone able to give blood can contact the Red Cross at redcrossblood.org or by calling 1-800-RED CROSS.
More than 480,000 customers were without power in the Southeast, roughly 136,000 of which were Georgia Power Co. customers, the utility said.
South Carolina was the hardest hit, with about 220,000 customers without electricity, while Wilmington, North Carolina, accounted for more than 58,000 outages.
The utilities said Wednesday morning they expect those numbers to rise over the next 24 hours.
Georgia Power, the state's largest utility, warned that hundreds of thousands could be without electricity for days.
"This has the opportunity to be a huge event when you're talking about the amount of ice you're looking at," Aaron Strickland, Georgia Power's emergency operations chief, told reporters.
The utility staged fleets of trucks across the area. Teams from Florida, Texas and Ohio bolstered local line crews.
Closings and cancellations
Throughout the Southeast, hundreds of businesses, churches, government offices and school systems were closed because of the weather.
Among the cities with lengthy lists of closings were Atlanta; Nashville; Birmingham, Alabama; Baton Rouge, Louisiana; Charleston and Columbia, South Carolina; Memphis, Tennessee; Little Rock, Arkansas; and Charlotte.
All Georgia government offices will be closed Thursday as well, the governor said.
In Atlanta, the U.S. Women's National Team postponed a soccer match with Russia set for Wednesday. The game was moved to 7:30 p.m. Thursday.
The storm system also was taking its toll on travel.
Amtrak suspended some rail service in the Northeast, South and Mid-Atlantic regions for Wednesday.
Nationwide, more than 3,100 flights were canceled, according to FlightAware.com; more than 1,600 of the 2,500 scheduled departures and arrivals at Atlanta's Hartsfield-Jackson International Airport were among the cancellations.
Charlotte Douglas International and Raleigh-Durham International airports accounted for the majority of other flights canceled.
Georgia's Department of Transportation put crews on 12-hours shifts to salt, sand and scrape the roadways.
Deal said the state has brought in an additional 180 tons of salt and sand, and he urged Georgian not to put themselves "in jeopardy or danger."
South Carolina Gov. Nikki Haley dispatched additional Highway Patrol officers to help with the expected accidents and stranded motorists on state highways, her office announced.
At least nine deaths have been blamed on the weather, including two people who were killed in Georgia and two who died in North Carolina, authorities said.
In Texas, three people died when an ambulance driver lost control on an icy patch of road outside of Carlsbad.
The ambulance slid off the roadway into a ditch, where it rolled over, caught fire and burned, the Texas Department of Public Safety said. A patient, a paramedic and another passenger were pronounced dead at the scene.
"If you get even a 10th of inch of ice on a road, it's like a skating rink," said Kurt Van Speybroeck, a National Weather Service meteorologist in Dallas.
In Mississippi, authorities blamed the storm for two traffic deaths.
-- CNN's Ed Payne, Tom Watkins, Steve Almasy, Stephanie Gallman, Carma Hassan, Dave Alsup and Sean Morris contributed to this report.