As the U.S. prepares for one of the busiest travel weekends of the year, the threat of severe weather has already led to hundreds of flight cancellations.

As CNN reported, tornado warnings were issued in the southern states of Texas and Louisiana on Thursday. In Texas, the Federal Aviation Administration ordered ground stops at two airports, CBS reported. Texas Governor Greg Abbott activated emergency resources in the state on Thursday.

“Several areas across the U.S. will be monitored for potentially hazardous weather for several days leading up to and following New Year’s Day,” the National Weather Service wrote in a post on X.

According to Flight Aware, nearly 800 flights were canceled in the U.S. on Thursday and more than 90 flights had already been canceled on Friday. Seven flights were preemptively canceled for Saturday.

In a statement on Saturday, even though details such as how severe the threat will be and the “exact corridor” remain uncertain, Bentley said, “we are increasingly concerned that there will be a lot of storms with a severe weather threat.”

“We expect multiple rounds of storms with the potential for everything from hail to winds to potential tornadoes,” Bentley said. “As it is a fairly active time of year for leisure travel, we want to ensure that anyone staying in or traveling through this corridor is aware of the weather hazard.”

He added: “Ensure that if you are in this part of the country on Saturday you have multiple options for watches and warnings and that you keep an eye on the weather forecast for everything that can change as it gets closer.”

According to the TSA, nearly 40 million travelers are expected to be screened by the Transportation Security Administration (TSA) between December 19 and January 2, an increase from last year. Friday, December 27, is expected to be one of the three busiest days during this period, the TSA wrote on X.

The AAA predicted that more than 100 million people would walk 50 miles (80 km) or more between December 21 and January 1.