(CNN): More than 600 US flights have been canceled on Monday as winter weather bears down on a wide swath of the United States.
As of 11:30 a.m. ET, about 660 flights within, into or out of the US had been canceled Monday, according to flight tracking site FlightAware. About 1,500 flights were delayed.
The bulk of the cancellations so far are affecting Dallas Love Field and Dallas-Fort Worth International airports in Texas, with about 100 cancellations to or from Denver International Airport in Colorado.
There’s a winter storm warning in effect for a large portion of Texas, including the Dallas-Fort Worth area, until 6 a.m. Central Time on Wednesday.
Dallas-based Southwest Airlines had canceled about 330 flights within, into or out of the US by 11:30 a.m. ET on Monday.
The airline, which had an operations meltdown over the holidays, issued a winter weather waiver on Sunday and extended the waiver on Monday to eight airports in Texas and Oklahoma. The waiver applies to travel from January 30 to February 1.
American Airlines issued a waiver on Sunday for Dallas-Fort Worth International Airport that applies to travel from January 29 to February 2. American had canceled 115 US flights by 11:30 a.m. ET Monday.
Regional carrier SkyWest had canceled about 100 flights by midday Monday.
Dallas Love Field tweeted on Monday that its team “stands ready to treat and clear surfaces to allow for safe operations.” DFW is also preparing for bad weather.
Both airports urged travelers to check with their airlines for flight status. DFW advised travelers to check before coming to the airport.
The weather will also make for treacherous road conditions. Up to a half an inch of ice or sleet is possible in parts of Texas, the National Weather Service warns. Ice accumulation is expected across at least 15 states, the National Weather Service’s Weather Prediction Center said.
“If you must travel, slow down and use extreme caution particularly when approaching bridges and overpasses,” the Texas warning says.