A winter storm disrupting large parts of the United States has driven widespread air-travel cancellations and growing power outages, as officials prepared for a mix of snow, sleet, and freezing rain to extend across much of the eastern two-thirds of the country.

Airlines cancelled more than 4,000 flights scheduled for Saturday, with disruptions concentrated around major air corridors and hubs, as carriers warned of last-minute changes and continued to adjust schedules into the start of the new week.

Power outages expanded through Saturday night, reaching more than 160,000 customers by 10:17 p.m. Eastern time, with the largest concentrations reported in Louisiana and Texas and outages extending as far west as Texas.

Federal actions and emergency posture also escalated as the storm spread: President Donald Trump described the system as “historic” and approved federal emergency disaster declarations for South Carolina, Virginia, Tennessee, Georgia, North Carolina, Maryland, Arkansas, Kentucky, Louisiana, Mississippi, Indiana, and West Virginia.

The Department of Homeland Security said 17 states, as well as Washington, D.C., had declared weather emergencies, while DHS Secretary Kristi Noem said tens of thousands of residents in affected southern states were without power and that utility crews were working to restore service.

Energy-system preparations moved in parallel with the weather response: the U.S. Department of Energy issued an emergency order allowing the Electric Reliability Council of Texas to tap backup generation at data centers and other large facilities, aiming to curb blackouts as temperatures fell.

Forecast guidance pointed to a prolonged event, with the National Weather Service cautioning the storm was unusually large and long-lasting and warning of the potential for widespread and heavy ice build-up across the southeastern United States, alongside record cold and dangerous wind chills pushing deeper into the Great Plains by Monday.

Airline cutbacks expanded into Sunday and early week operations, with more than 9,400 flights planned for Sunday called off; Delta said it was adding cancellations for Atlanta and along the East Coast, including Boston and New York City, while redeploying de-icing and baggage specialists to several southern airports.

JetBlue said it had scrapped about 1,000 flights through Monday with further cancellations possible, and United said it had been proactively cancelling some services in locations expected to be hit hardest as the freeze intensified.

Confirmed vs unclear: What is confirmed is more than 4,000 Saturday flight cancellations, more than 9,400 Sunday cancellations, and more than 160,000 customers without power by late Saturday; what’s still unclear is how quickly flight schedules and outage totals will change as the storm lingers into next week.

As the storm’s footprint widens and conditions evolve, the operational focus remains on maintaining grid resilience, restoring electricity, and keeping transportation services aligned with the latest weather impacts.