Millions of Americans endured a slow, slippery return to work Monday as the Eastern Seaboard dug out from a record-setting blizzard that killed at least 41 people.

Transit systems and airports were recovering from a weekend of paralysis, but forecasters warned that refreezing of melting snow could make roads slick and dangerous.

Non-essential federal workers were ordered to stay home in Washington, D.C., Maryland and Virginia as officials encouraged residents to stay off the roads and allow the blizzard cleanup effort to continue.

The storm dropped snow from the Gulf Coast to New England and was the second-biggest in New York City history, with 26.8 inches measured in Central Park by midnight Saturday, just shy of the record 26.9 inches set in 2006, the National Weather Service said.

Worst-hit was the eastern panhandle of West Virginia, with 42 inches recorded at Glengary and 40.5 inches in Shepherdstown.

In many areas, temperatures rose above freezing Sunday, melting some snow but creating a new hazard: black ice.

"Melting and refreezing will be the theme of this week," NBC Connecticut meteorologist Tyler Jankoski said. "Use caution and watch for black ice in the mornings."

Many roads were suffering from severe choke points where snow piles were blocking traffic lanes, NBC New York reported.

In Pennsylvania, an eight-months' pregnant teen was among those who died shoveling snow over the weekend, her family said, while a man who tried to dig out his car in Muhlenberg Township was buried by a snowplow.

In the New York suburb of Passaic, New Jersey, a woman and her 1-year-old son died of carbon monoxide poisoning while waiting in their car as the woman's husband cleared the drive. Their 3-year-old daughter was in critical condition, police said.

Airports were slowly returning to normal, but more than 1,800 arrivals and departures had been canceled at airports in the storm zones at 3:30 p.m. ET. Five hundred were canceled at Newark Liberty International Airport in New Jersey.

United Airlines said it was bringing workers from Chicago and Houston to help clear a backlog of stranded passengers at its hub at Newark and at Washington Dulles in suburban Virginia, where 30 inches of snow fell.

Amtrak said it would run "modified" service on the Northeast corridor Monday, while the D.C. Metro transit system was operating over a limited area.

Pennsylvania Gov. Tom Wolf apologized Monday to hundreds of motorists who were stranded on a stretch of the Pennsylvania Turnpike about 80 miles southeast of Pittsburgh, many of them for most of the weekend.

About 500 vehicles got stuck after two tractor-trailers conked out while trying to climb a grade to the Allegheny tunnels got stuck Friday night, NBC station WPXI of Pittsburgh reported. It took until Sunday afternoon for all vehicles and travelers to be safely removed, the Pennsylvania Turnpike Commission said Monday.

The New York transit authority reported good service said along most services city subway lines for the afternoon commute.

The city appealed for emergency snow laborers to remove snow and ice from bus stops, crosswalks and fire hydrants, starting at $13.50 per hour. "This was one of the worst storms to ever hit New York City, and we need all hands on deck to dig us out," Mayor Bill de Blasio said.

Officials brought in 500 pieces of special equipment from as far away as upstate New York and Canada to help with the cleanup in Baltimore, where more than 2 feet of snow blanketed the ground Monday.

"Needless to say, the recovery is going to take time," Mayor Stephanie Rawlings-Blake said at a news conference. "Removal efforts are far more complicated than just pushing 3 or 4 inches off to the side. [On] so many of our small streets, and even for our larger roads, the crews literally need to lift the snow up, put it in a dumpster and carry it out of the neighborhood."

In Virginia, Gov. Terry McAuliffe said the cost of cleaning up the snowstorm would run $2 million to $3 million per hour, easily making it the most expensive snow event in the state's history.

"Please stay off the roads," McAuliffe said. "Give us the time to do what we need to do." (Source: NBC News)

Story Date: January 26, 2016