The seemingly endless winter dumped a half a foot snow on the ground in parts of the South, Mid-Atlantic and Northeast, and many areas Tuesday morning saw something even more unusual in March: a blast of arctic air that sent temperatures plummeting into the single digits.

Baltimore-Washington International Thurgood Marshall Airport broke a 141-year-old record low temperature, reaching 4 degrees. The National Weather Service said the low reached early Tuesday broke a 5-degree record set on the day in 1873. It was also a record low for the month of March. Dulles International Airport — also outside Washington — tied a 1993 record for the month at -1 degree.

Both airports broke record lows two days in a row.

Schools and government offices along the East Coast were closed Tuesday or delayed opening. And Virginia State Police said slickened roads were factors in three traffic deaths.

Blame it on a return of the “polar vortex.”

“That is the buzzword this winter, the polar vortex. That cold air just kind of migrates around the poles and the extreme northern latitudes all the time,” said Jim Lee, meteorologist in charge at the National Weather Service in Sterling, Va. “The jet stream enables that colder air to move down the East Coast.”

Monday’s snowstorm followed a pattern that’s become routine. Schools and government offices were closed. Federal workers stayed home — the fourth weather-related shutdown this season. Young adults gathered on the sloppy, slushy National Mall for a semi-organized, afternoon snowball fight.

Tourists, who flock to the nation’s capital 365 days a year, were seeking out whatever activities they could find.

The National Air and Space Museum was the only Smithsonian institution open, and it drew a crowd. Among the visitors were Russ Watters, 60, of St. Louis, and his 14-year-old son, Seth, who was touring Washington with his 8th-grade class.

“We’re trying to find stuff that’s open, so this is open,” Watters said.

The storm had a major effect south of the Mason-Dixon line. Governors declared states of emergency in Virginia and Tennessee, where there were hundreds of traffic accidents and tens of thousands of power outages. Nearly 3,000 flights were canceled Monday.

In Falls Church, Va., daredevils took advantage of another snow day by sledding down a steep hill behind an elementary school. Maya Luera, 11, said she wouldn’t be so happy in June, when the school year will be extended because there’s been so much snow.

“I’m more of a summer person, so I’d rather have more free time in the summer than the winter,” she said.

(AP)