More than 4,000 flights were cancelled in the US ahead of a monster winter storm that had already cut power to more than 230,000 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 today and into next week.
Calling the storms "historic," President Donald Trump 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," he wrote in a post on Truth Social.
Transportation Secretary Sean Duffy warned that up to 240 million people could be affected by the storm.
At least 20 states and the US capital Washington have declared states of emergency.
"Take this storm seriously, folks," the NWS said on X, predicting an "astonishingly long swath" of snowfall from Colorado to Maine.
The ongoing major winter storm will expand into the Mid-Atlantic states tonight and then the Northeast late Sunday. Heavy snow, sleet, and freezing rain will bring considerable impacts to much of the eastern half of the United States. pic.twitter.com/7TbzLLDJcU
— NWS Weather Prediction Center (@NWSWPC) January 24, 2026
"We do have tens of thousands of people in affected states in the South that have lost power," DHS Secretary Kristi Noem said late yesterday afternoon. "We have utility crews that are working to restore that as quick as possible."
The number of power outages continued to rise. As of 2am EST (7am Irish time) this morning, some 217,000 US customers had no electricity, the bulk of them in Louisiana, Mississippi, Texas and Tennessee, according to PowerOutage.com.
The Department of Energy issued an emergency order authorising the Electric Reliability Council of Texas to deploy backup generation resources at data centres and other major facilities, aiming to limit blackouts in the state.
The National Weather Service warned of an unusually expansive and long-duration winter storm that will bring widespread, heavy ice accumulation in the southeast, where "crippling to locally catastrophic impacts" can be expected.
Weather service forecasters predicted record cold temperatures and dangerously cold wind chills descending further into the Great Plains region by tomorrow.
Major US airlines warned passengers to stay alert for abrupt flight changes and cancellations.
US electric grid operators stepped up precautions to avoid rotating blackouts.
Dominion Energy D.N, 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-ever 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."
The brutal storm system is the result of a stretched polar vortex, an Arctic region of cold, low-pressure air that normally forms a relatively compact, circular system but sometimes morphs into a more oval shape, sending cold air spilling across North America.
Scientists say the increasing frequency of such disruptions of the polar vortex may be linked to climate change, though the debate is not settled and natural variability plays a role.
But Mr Trump - who has rolled back green energy policies - questioned how the cold front fit into broader climate shifts.
"WHATEVER HAPPENED TO GLOBAL WARMING???" he posted on Truth Social.
The NWS warned that heavy ice could cause "long-duration power outages, extensive tree damage, and extremely dangerous or impassable travel conditions," including in many states less accustomed to intense winter weather.
New York Governor Kathy Hochul warned residents to stay inside amid frigid conditions: "Five or six minutes outside could literally be dangerous for your health."
She stressed precautions like protecting pipes, using heaters safely, and checking on vulnerable neighbours.
Authorities warned of life-threatening cold that could last a week post-storm, especially in the Northern Plains and Upper Midwest, where wind chill lows were forecast to dip to extremes under -45C.
Such temperatures can cause frostbite within minutes.
