Deep South in winter storm emergency
The US Deep South, a region used to sultry weather and hurricane warnings, is preparing for a severe winter storm.
States of emergency have been declared in Georgia, Louisiana, Mississippi, North Carolina and South Carolina.
As many as 50 million people across the region could be affected in a winter storm over the next two days.
Many schools in the region are closed and road crews are at the ready. About 3,000 flights were grounded by weather on Tuesday.
Forecasters predicted up to 1ft (30.5cm) of snow in parts of Virginia and up to 10in along the North Carolina coast.
Motorists from Texas to Virginia have been warned to stay off the roads.
"This is a very dangerous situation because snow and ice are very rare," Robert Latham, executive director of the Mississippi Emergency Management Agency, told USA Today.
"We need everyone to have an emergency plan together for this."
The potential for ice was more of a concern than the snow totals, Jason Deese with the National Weather Service said.
Traffic came to a halt in the early afternoon in Atlanta as snow began falling and commuters tried to leave work early.
In northern Alabama, some schools held classes, but quickly had to change course, dismissing students early when the storm arrived earlier than predicted.
Officials feared icy road conditions would force hundreds of students to spend the night in classrooms or gyms.
"They have food and we have gas heat and the electricity is on, so that is a possibility," DeKalb County Emergency Management Director Anthony Clifton told the Associated Press news agency.
"We will have a campout before we will send them out into an unsafe situation."
Four people died in Itawamba County, Mississippi, when a fire destroyed a mobile home. Investigators believe a heater caused the blaze.
Parts of the US Midwest, meanwhile, were struggling through another bout of near-record cold temperatures.
Schools were closed in several central US states for a second consecutive day because of the cold.
Parts of Minnesota saw temperatures plunge to as low as 35 to 50 degrees below zero Fahrenheit as the state struggled with a shortage of natural gas due to an earlier pipeline explosion in Canada.
Residents in the US states of Ohio, Illinois and Pennsylvania also witnessed an unusual weather phenomenon.
Numerous naturally occurring donut-like snowballs - known as snow rollers and formed when wind blows snow along the ground - were reported.