Jan. 3 (UPI) -- More than 3,000 flights were canceled across the United States on Monday, many of them due to severe weather and staffing shortages brought on by increasing cases of COVID-19 -- an ongoing trend that began before Christmas.
More than 3,600 flights were canceled on Monday, according to FlightAware. Most of the cancellations were made at Reagan National Airport in Washington, D.C., Baltimore/Washington International Airport and LaGuardia Airport in New York City.
Some of the disruptions were caused by a severe winter storm in the Mid-Atlantic, which also closed schools and government offices on Monday.
Several inches of snow were forecast to fall in the Washington area on Monday. Mayor Muriel Bowser declared a snow emergency for most of the day.

Monday's cancellations follow thousands of other disrupted flights across the United States since the week of Christmas. More than 4,600 were canceled on Sunday.
Chicago O'Hare International Airport saw nearly a quarter of its flights canceled on Sunday, Denver International Airport canceled almost 20%, Houston Bush Intercontinental Airport 12% and Atlanta Hartfield-Jackson and Newark Liberty airports 11%.
There were more than 5,000 cancellations and almost 20,000 delays affecting U.S. flights over the weekend, making it the most affected two-day stretch of the holiday season for air travelers.
"It was absolute mayhem," said traveler Natasha Enos, according to USA Today.
Some airlines are paying their crews extra to avoid cancellations for the next few weeks. Last week, JetBlue canceled hundreds of flights through mid-January to avoid scrapping them at the last minute.