(Adds snowfall amounts, winter storm warnings, traffic accidents, wind-chill effect details)
By Rich McKay
ATLANTA, Jan 17 (Reuters) - A winter storm that caused at least four deaths in the U.S. South brought record low temperatures on Wednesday to parts of the region, where it coated roads with ice, snapped power lines and prompted public school closures.
Frigid temperatures and snow were also forecast for the mid-Atlantic region and much of New England through Thursday. The National Weather Service (NWS) issued winter weather advisories and storm warnings for northern Georgia into Virginia and from Massachusetts to Maine.
In Austin, Texas, a vehicle plunged more than 30 feet (9 meters) off a frozen overpass late on Tuesday, killing a man in his 40s, Austin-Travis County Emergency Medical Service said on its Twitter feed.
An 82-year-old woman who suffered from dementia was found dead on Wednesday behind her Houston-area home, likely the victim of exposure to the cold, the Harris County Sheriff’s Office said.
In Georgia, two people were fatally struck by a car that slid on an ice patch near Macon, local media said.
At Atlanta’s Hartsfield-Jackson International Airport, the nation’s busiest with a typical volume of 2,700 arrivals and departures a day, about 470 flights had been canceled by Wednesday afternoon, according to tracking service Flightaware.com.
The sheriff’s office in Oconee County, Georgia, east of Atlanta, tried humor to keep people off icy roads.
“I know you need cigarettes, beer and wine to get you through having your kids at home. Can you just do without for a day? Stay home,” the office said on its Facebook page.
Wednesday’s storm was not the first this winter to bring a blast of frosty weather to the South, where parts of Florida and the Louisiana coast saw their first measurable snowfall in decades.
Winter storm warnings and winter weather advisories were posted across portions of the Carolinas and southern Virginia.
The governors of Georgia, North Carolina and Louisiana declared states of emergency because of severe conditions that made roads treacherous. In North Carolina, where more than 2,000 snow-plow personnel worked to clear roads, the state Highway Patrol reported nearly 1,600 traffic accidents during the first 12 hours of Wednesday.
More than 9 inches (23 cm) of snow has fallen in Durham, North Carolina, since Monday, with 6 inches (15 cm) or more measured at various locations across southern Virginia, the NWS said.
North Carolina Governor Roy Cooper warned at a news briefing that cold temperatures Wednesday night would make travel conditions even more hazardous.
“The snow is pretty but don’t be fooled,” Cooper said.
In Atlanta, many people appeared to be heeding Georgia Governor Nathan Deal’s plea to stay off the roads as only a few cars crept along on typically packed highways.
A few people bundled up to go out in temperatures that were well below freezing in a city known for its sweltering summer heat.
“We don’t dare try to get the car out of the garage,” said teacher Kimberly Hodges, 40, who was walking her puppy in the city’s East Atlanta Village neighborhood. “It’s a mess out here.”
The weather in Atlanta is not expected to get above freezing until Thursday afternoon. State government offices and many schools were expected to remain closed until at least then.
Wind chill advisories in the mountains of North Carolina warned that temperatures would feel like they had fallen to 10 degrees below zero Fahrenheit.
In Houston, the nation’s fourth most populous city, most freeways were closed on Wednesday morning after icing over, the city’s Office of Emergency Management said.
In storm-hit North and South Carolina, more than 32,000 homes and businesses were without power by Wednesday afternoon, utilities data showed. (Additional reporting by Gina Cherelus in New York, Jon Herskovitz in Austin, Texas; Writing by Jon Herskovitz; Editing by Tom Brown and Paul Tait)