Thousands of flights were canceled Thursday as Winter Storm Landon brings ice and snow to Texas and the midwest, up through the northeast.

At least 4,740 flights were canceled within, into, or out of the United States, according to flight tracking company FlightAware.

Texas saw high rates of flight cancellations. Dallas-Fort Worth International Airport has canceled 645 outbound flights, which is far and away the most in the country, according to FlightAware. The cancellations account for 67 percent of the airport’s flights. Similarly, 179 flights were nixed at Dallas Love Field Aiport, which is 82 percent of departures. Austin Bergstrom International Airport called off 227 outbound flights or 79 percent of flights.

A significant number of departures were called off at Midwest airports as well. Data from FlightAware shows 268 departures or 25 percent of flights out of Chicago O’Hare International have been canceled. Nearly 110 or 80 percent of flights at John Glenn Columbus International Airport in Ohio were axed.

In terms of airlines, Southwest has called off the highest number of flights at 1,053, accounting for 30 percent of the airline’s departures. American Airlines has canceled 24 percent or 716 scheduled flights. Envoy Air nixed 61 percent of flights, while Air Wisconsin and GoJet called off 45 and 43 percent of flights, respectively.

The slew of cancellations comes as Winter Storm Landon wreaks havoc on America’s heartland.

According to Weather.com:

In Dallas-Fort Worth, freezing rain Wednesday night changed to a sleet and snow mix by Thursday morning, leaving roads hazardous and prompting a closure of Dallas-Fort Worth International Airport.

Freezing rain has pushed as far south as the Austin and San Antonio metro areas, which prompted the closure of elevated stretches of at least two roads in northern Bexar County.

Five to six inches of snow was measured in Tulsa, Oklahoma, while Oklahoma City picked up 3 to 5 inches. At least a quarter inch of ice accumulation was reported in Hugo, Oklahoma.

Ice accumulations have been reported in Little Rock, Arkansas, Columbus and Cincinnati, Ohio, Pittsburgh, Pennsylvania, and other areas. Parts of Tennessee, Kentucky, Missouri, Mississippi, Indiana, Ohio, and Illinois are under an ice storm warning from the National Weather Service.