Nearly 300,000 homes and businesses in Texas are without electricity as a winter storm dumps ice across the region, downing power lines and disrupting flights. 

Most of the outages Wednesday were in central and eastern Texas, according to PowerOutage.us. Austin Energy, which had about 157,000 customers in the dark, warned some may be without power for 12 to 24 hours.  

The ice storms across Texas, Oklahoma, Arkansas, and Mississippi are expected to continue through Thursday before moving east and turning to rain, said Bob Oravec, a senior branch forecaster at the US Weather Prediction Center. Ice-storm warnings and winter-weather advisories stretch from Texas to Tennessee, according to the National Weather Service.

American Airlines Group Inc. canceled 1,162 flights Wednesday, primarily at Dallas-Fort Worth International Airport. Departures at the airport were in the single digits per hour, the carrier said. 

Southwest Airlines Co. grounded 499 flights at nearby Dallas Love Field, according to FlightAware.com. 

The two airports accounted for the vast majority of 1,975 US cancellations reported Wednesday by the flight-data tracker.