Thousands of flights are delayed or grounded days before Christmas as a powerful arctic blast rocks the U.S., moving its way to the eastern portion of the country.

The storm has already spurred plummeting temperatures across the country, as some areas saw subzero temperatures with wind chills going as low as minus 40.

Denver, Colorado, for instance, saw temperatures plummet 37 degrees in the span of an hour this week, and Cheyenne, Wyoming, broke a record on Wednesday as temperatures fell 40 degrees in a 30 minute time span.

According to the National Weather Service, over 200 million people, or 60 percent of the U.S. population, are under some sort of winter storm warning or advisory.

Airport crews clear snow at O’Hare International Airport in Chicago, Thursday, Dec. 22, 2022. (AP Photo/Nam Y. Huh)

Fight cancellations are piling up as a result of the storm. According to 10:45 a..m. ET data from FlightAware, there were over 3,600 flight cancellations within, into, or out of the country on Friday alone, and delays were already over 2,900, just two days before Christmas.

That is on top of the cancellations and delays experienced Thursday, as 2,685 U.S.-related flights were cancelled and 11,290 more were delayed.

A man braves sub zero temperatures with heavy winds as he uses a snowblower Friday, Dec. 23, 2022, in Fox Point, Wis. Winter weather is blanketing the U.S. as a massive storm sent temperatures crashing and created whiteout conditions. (AP Photo/Morry Gash)

 The NWS warns that the storm will continue to cause what it described as “widespread disruptions to large portions of the nation heading into the holiday weekend,” ranging from the Canadian border to Florida:

An immense winter storm that has brought a frigid blast to much of the CONUS along with impactful winter precipitation will persist in tracking across the eastern U.S. today. Winter weather hazards remain in effect from the Canadian border south to the Rio Grande, Gulf Coast and central Florida Peninsula while spanning from the Pacific Northwest to the Eastern Seaboard. The National Weather Service’s Watch Warning graphic ( https://www.weather.gov/) depicts one of the greatest extents of winter weather warnings and advisories ever. As of early Friday morning, over 240 million of people within the United States are under some form of winter weather warning or advisory.

Updated flight cancellation tallies and travel information can be found here.