Thousands of flights across the U.S. were canceled or delayed Monday as powerful storms swept across the eastern half of the country and a partial government shutdown affecting airport security screeners dragged into a second month.

The disruptions come at an already challenging time for air travel, in part because the shutdown that began Feb. 14 has strained staffing at some security checkpoints. At the same time, airports are crowded with spring break travelers and fans heading to March Madness games, the annual NCAA men’s and women's college basketball tournaments.

Flight delays and cancellations piled up Monday at some of the nation’s largest airports, including those in New York, Chicago and Atlanta. The storm system that dropped snow by the foot in the Midwest was barreling toward the East Coast with dangerously high winds and the potential for “producing strong and long track tornadoes,” the National Weather Service warned Monday.

More than 3,900 flights scheduled to fly into, out of or within the U.S. on Monday have been called off, according to flight-tracking site FlightAware. Roughly 8,200 other U.S. flights were delayed.

Kelly Price, who was trying to get home to Colorado after a family vacation in Orlando, Florida, said her Sunday night flight wasn’t canceled until early Monday.

“By that time the only place for us to sleep was the airport floor. So we’re all tired and frustrated,” she said, adding that the soonest flight she and her family could book doesn’t leave until Tuesday afternoon.

The nationwide cancellations included more than 500 in and out of Chicago O’Hare International, 350 at Atlanta’s Hartsfield-Jackson International and over 260 at John F. Kennedy International Airport, according to FlightAware.

Earlier Monday, citing severe weather, the Federal Aviation Administration ordered ground stops at Hartsfield-Jackson and Charlotte Douglas International Airport, along with ground delays at JFK and Newark Liberty International Airport.

Danielle Cash found herself stranded in St. Louis on Sunday while trying to get home to Tampa, Florida, after a weekend girls’ trip to Las Vegas. Now she’s spending several hundred dollars more than planned on a hotel room in a snowy city she wasn’t dressed for.

“It was 80 degrees in Tampa when I left and then going to Vegas," she said. “And it was 90 degrees in the desert.”

Cash said she’s now booked on a flight that will take her to Tennessee before finally returning to Tampa by Tuesday afternoon.

The storms are also unfolding just as airport security screeners missed their first full paycheck over the weekend. The current partial government shutdown affects only the Department of Homeland Security, which includes the Transportation Security Administration.

Democrats in Congress have said Homeland Security won’t get funded until new restrictions are placed on federal immigration operations following the fatal shootings of Alex Pretti and Renee Good in Minneapolis earlier this year.

It is the third shutdown in less than a year to leave TSA workers temporarily without pay. Once the government reopens, employees will have to wait for back pay.

Some airports have reported longer security lines because of staffing shortages as more TSA workers take on second jobs, can’t afford gas to get to work or leave the profession altogether. Homeland Security has said more than 300 TSA agents have quit since the start of the shutdown.

TSA union leaders held a news conference Monday outside Hartsfield-Jackson in Atlanta, warning that air travelers could face increasingly long wait times as the shutdown continues. Even so, union leaders said, many officers are still reporting to work despite mounting financial strain.

Many TSA workers “are coping with eviction notices, vehicle repossessions, empty refrigerators and overdrawn bank accounts,” said Aaron Barker, a local leader with the American Federation of Government Employees. Supporters behind him held signs reading, “We want a paycheck, not a rain check.”

“To be quite frank, officers are pissed off,” Barker said. “And we’re not just talking about here in Atlanta — we’re talking about nationwide.”

The airport in Austin, Texas, shared a video on X taken at 5:30 a.m. local time showing the security line spilling out onto the sidewalk outside.

“We continue to recommend arriving 2 1/2 hours before your domestic flight,” Austin-Bergstrom International Airport said.

Travelers flying out of Louis Armstrong International Airport in New Orleans on Sunday and Monday were also advised to arrive at least three hours early "due to impacts from the federal government's partial shutdown,” the airport said on X.

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Associated Press video journalist Emilie Megnien in Atlanta contributed to this report.