The winter storm currently moving through the middle of the U.S. to the East Coast has caused thousands of flights to be delayed or canceled entering Monday.

Hundreds of flights across the U.S. were delayed Monday morning after more than 8,000 were delayed each on Saturday and Sunday, according to the flight tracking website FlightAware. The Weather Channel, which dubbed the storm Winter Storm Blair, said that some areas like northeast Kansas have received over a foot of snow already.

Over 1,400 flights have been canceled across the U.S. Monday, with the most impacted airports including Reagan National, Baltimore/Washington International Thurgood Marshall Airport, and Dulles International Airport in Virginia. Some Midwestern airports like St. Louis Lambert International and Kansas City International are also still affected after being heavily impacted over the weekend, per FlightAware data.

Southwest (LUV) and American Airlines (AAL) each had hundreds of combined cancellations and delays Monday morning, with other airlines like United (UAL), JetBlue (JBLU), and Delta Air Lines (DAL) delaying or canceling dozens of flights, according to FlightAware.

The National Weather Service said in its latest update Monday that it still expects "moderate to heavy snow from the Ohio Valley to the Mid-Atlantic" through Monday night with the expectation of "severe travel delays."

Some areas of the country like Washington, D.C. could get up to a foot of snow by the time the storm passes, while it could also produce freezing rain across the affected area. Warmer areas into the South could also experience severe thunderstorms, the NWS said.

Several states declared states of emergency as the storm rolled across the region this weekend. A number of officials like Kentucky Gov. Andy Beshear and Virginia Gov. Glenn Youngkin told residents to stay off the roads or adjust the timeline of their travel plans if possible.