With much of the eastern part of the country covered by a blizzard, airlines have been forced to cancel thousands of flights for Friday and Saturday.

The airline tracker FlightAware reports that 2,947 flights within, into or out of the U.S. have been cancelled today. A quarter of American Airlines’ flights have been cancelled today alone.

There are already 3,543 cancellations for flights in the U.S. on Saturday. American Airlines cancelled 28 percent of its Saturday flights, while Southwest cancelled 19 percent of its flights. United cancelled 31 percent.

One plane that tried to take off from Chicago’s O’Hare International Airport on Friday ran into some trouble. According to NBC Chicago, a United Airlines flight from San Francisco skidded onto snow-covered grass while trying to land. Thankfully, there were no injuries reported.

As previously noted, the Weather Channel has said that the storm is expected to affect over 85 million people and parts of 20 states are under blizzard warnings.