Commuters faced slippery, slush-covered roads on Friday after yet another winter storm brought snow and ice to the East Coast, leaving at least 21 people dead, including a pregnant woman struck by a mini-plow in New York City whose baby was then born by cesarean section in critical condition.

The latest go-round of bad weather began overnight in some places — just in time to delay tens of thousands of deliveries of Valentine’s Day flowers — as sleet and rain fell on roads already covered in many parts of the Northeast with deep puddles and icy patches.

The sloppy mix of snow and face-stinging sleet grounded more than 6,500 flights nationwide on Thursday and closed schools, businesses and government centers. About 1.2 million utility customers lost power as the storm moved from the South through the Northeast, dropping to about 550,000 outages, mostly in South Carolina and Georgia.

“Every time it snows, it’s like, “Oh, not again,'” said Randal DeIvernois of New Cumberland, Pa., which had about 10 inches of snow by midafternoon Thursday. “I didn’t get this much snow when I lived in Colorado.”

By Friday morning, the number of flight cancellations dropped to about 1,110 nationwide. Many schools remained closed in Connecticut, Maine, Massachusetts, New Hampshire, New York state, Pennsylvania, Vermont and Virginia, while some in Rhode Island were opening late.

The treacherous weather was blamed for nearly two dozen deaths, many of them in motor vehicle accidents.

In New York, Min Lin, 36, died after she was struck by a utility vehicle with a snowplow attached to it as it backed up outside a shopping center in Brooklyn. She was rushed by paramedics to a nearby medical center, where her nearly full term, 6-pound, 6-ounce baby was delivered via cesarean section, hospital spokeswoman Eileen Tynion said.

The baby was in critical condition in the neonatal intensive care unit, she said.

No immediate charges were brought against the snowplow operator.

The snow, sleet and ice that bombarded the Southeast on Wednesday brought its ferocity into the Northeast a day later.

Washington, D.C., residents received 9 inches of snow Thursday, Westminster, Md., reported 19 inches, and Newark, Del., had 14 inches.

Philadelphia had nearly 9 inches, its fourth 6-inch snowstorm of the season — the first time that has happened in the city since record-keeping began in the late 1800s. New York City received nearly 10 inches, and parts of New Jersey had more than 11.

In New York City, the teachers union and TV weatherman Al Roker harshly criticized Mayor Bill de Blasio’s decision to keep schools open. Roker, who was in Russia for the Winter Olympics but has a daughter in New York’s public schools, said on Twitter: “It’s going to take some kid or kids getting hurt before this goofball policy gets changed.”

The mayor said many parents depend on schools to watch over their children while they are at work.

Across the South, the storm left in its wake a world of ice-encrusted trees and driveways and snapped branches and power lines.

In Bonneau, S.C., Jimmy Ward and his wife, Cherie, lost power and spent Wednesday night in their home, warming themselves in front of a gas log fire.

But after running low on propane, they headed Thursday night to a hotel, where it was expected to be cozier but a lot less exciting than the night before.

“From 2 o’clock yesterday until this morning, it just sounded like gunfire — all the trees popping and falling,” Cherie Ward said.

In North Carolina, where the storm caused huge traffic jams in the Raleigh area on Wednesday as people left work and rushed to get home in the middle of the day, National Guardsmen in high-riding Humvees patrolled the snowy roads on Thursday, looking for any stranded motorists.

Around the country, this is shaping up as one of the snowiest winters on record. As of early this month, Washington, Detroit, Boston, Chicago, New York and St. Louis had gotten roughly two or three times as much snow as they normally receive at this point in the season.

The procession of storms and cold blasts — blamed in part on a kink in the jet stream, the high-altitude air currents that dictate weather — has cut into retail sales across the U.S., the Commerce Department reported Thursday. Sales dipped 0.4 percent in January.

This latest round of bad weather threatens to disrupt Friday’s deliveries of flowers for Valentine’s Day.

“It’s a godawful thing,” said Mike Flood, owner of Falls Church Florist in Virginia. “We’re going to lose money. There’s no doubt about it.”

Ronald Reagan Washington National Airport was virtually silent Thursday, with all flights canceled. Travelers tried to catch some sleep in the terminals.

Rob Wolcott, of Washington, and his wife were trying to reach the Caribbean island of St. Kitts, where he was planning to officiate at a friend’s wedding on Saturday.

The future bride and groom are “a little stressed,” Wolcott said. “But they’ll figure something out. They will still get married, whether or not I am the one to do the actual officiating.”

(AP)