More than 4,000 flights have been cancelled in the US ahead of a monster winter storm that has already cut power to more than 100,000 customers as far west as Texas, and threatened to paralyse eastern states with heavy snowfall.
Forecasters said snow, sleet and freezing rain, accompanied by dangerously frigid temperatures, would sweep the eastern two-thirds of the nation on Sunday and into next week.
Calling the storms "historic", President Donald Trump on Saturday approved federal emergency disaster declarations in South Carolina, Virginia, Tennessee, Georgia, North Carolina, Maryland, Arkansas, Kentucky, Louisiana, Mississippi, Indiana, and West Virginia.
"We will continue to monitor, and stay in touch with all states in the path of this storm. Stay safe, and stay warm," Mr Trump wrote in a post on Truth Social.
Seventeen states and the District of Columbia have declared weather emergencies, the Department of Homeland Security said.
"We do have tens of thousands of people in affected states in the south that have lost power. We have utility crews that are working to restore that as quick as possible," Homeland Security Secretary Kristi Noem said late Saturday afternoon.
The number of power outages continued to rise.
As of 6:30pm US eastern time, more than 130,000 US customers had lost electricity, the bulk of them in Texas and Louisiana, according to PowerOutage.com.
The US National Weather Service warned of an unusually expansive and long-duration winter storm that will bring widespread, heavy ice accumulation in the south-east US and cited "crippling to locally catastrophic impacts".
Weather service forecasters predicted record cold temperatures and dangerously cold wind chills descending further into the Great Plains region of the US by Monday.
Air travel disruptions
As of 6:42pm ET, more than 4,000 US flights scheduled for Saturday had been cancelled, according to flight tracking website FlightAware. More than 9,000 US flights originally set for Sunday have also been cancelled, the website indicated.
Major US airlines warned passengers to stay alert for abrupt flight changes and cancellations.
In an update on its website on Saturday morning, Delta Air said it "continues to make schedule adjustments due to Winter Storm Fern," with additional cancellations in the morning for Atlanta and along the East Coast, including Delta hubs in Boston and New York City.
The airline said it was relocating experts from cold-weather hubs to support de-icing and baggage teams at several southern airports.
JetBlue said as of Saturday morning it had cancelled about 1,000 flights through Monday, with additional cancellations possible, as it was "closely monitoring" forecasts for the storm.
US electric grid operators on Saturday stepped up precautions to avoid rotating blackouts.
Dominion Energy, whose Virginia operations include the largest collection of data centres in the world, said if its ice forecast holds, it could be among the largest winter events to affect the utility's operations.
Ms Noem, speaking at a news conference about US government preparations for the storm, warned Americans to take precautions.
"It's going to be very, very cold," Ms Noem said.
"So we'd encourage everybody to stock up on fuel, stock up on food, and we will get through this together."
Bracing for the biggest ice storm in a decade
Officials in Georgia advised people in the state's northern regions to get off the roads by sundown on Saturday and be prepared to stay put for at least 48 hours.
Will Lanxton, the senior state meteorologist, said Georgia could get "perhaps the biggest ice storm we have expected in more than a decade", followed by unusually cold temperatures.
"Ice is a whole different ball game than snow," Mr Lanxton said.
"Ice, you can't do anything with. You can't drive on it. It's much more likely to bring down power lines and trees."
Crews began treating highways with brine after midnight Saturday, with 1,800 workers on 12-hour shifts, Georgia Department of Transportation Commissioner Russell McMurry said.
"We're going to do what we can to keep the ice from sticking to the roads," Mr McMurry said. "This is going to be a challenge."
After earlier putting 500 National Guard members on stand-by, Georgia Governor Brian Kemp announced on Saturday that he was deploying 120 of them to north-east Georgia "to further strengthen our response in the hardest-hit areas".
After sweeping through the south, the storm was expected to move into the north-east, dumping snow exceeding 30 centimetres, the weather service predicted.
"Please, if you can avoid it, do not drive, do not travel, do not do anything that can potentially place you or your loved ones in danger," New York City Mayor Zohran Mamdani said Saturday.
"Instead, I urge every New Yorker who can to put a warm sweater on, turn on the TV, watch Mission Impossible for the 10th time, above all to stay inside."
Frigid temperatures affect the Midwest and north
The Midwest saw windchills as low as -40C, meaning that frostbite could set in within 10 minutes.
The -38C reading in Rhinelander, Wisconsin, on Saturday morning was the coldest in almost 30 years.
In Minneapolis, the worst of an extreme cold wave was over, but protesters calling for US Immigration and Customs Enforcement to leave Minnesota on Saturday still faced an outdoor temperature of -21C.
Reuters/AP
