Thousands of flights were cancelled across the eastern U.S. due to high winds and possible tornadoes, while the Midwest also experienced blizzard conditions. According to flight-tracking website FlightAware, 3,573 flights had been cancelled, with Chicago's O’Hare International Airport accounting the highest number of cancellations. Delays for flights within, into, or out of the US were also widespread, reaching 6,577 as of 2 p.m. The National Weather Service (NWS) has issued tornado watches for more than 34 million people across the region.