A fast-moving, thunder-carrying blizzard moved into the nation’s capital Friday afternoon, shutting down much of the government for business with the promise of record-breaking snowfall and pounding winds that would wreak havoc for much of the East Coast.

“We see this as a major storm,” Mayor Muriel Bowser said during a Friday news conference at the District of Columbia’s emergency operation center. “It has life-and-death implications.”

Snow began falling in Washington about 1 p.m., local time, softly at first, gently enveloping the monuments, with heavier snowfall arriving Friday night that was expected to continue past midnight Saturday.

Blizzard warnings were expanded Friday to include New York and Philadelphia, in addition to Washington and Baltimore.

“Potential life-threatening conditions are expected through Saturday night,” the National Weather Service reported.

At least nine people were killed in storm-related crashes in Kentucky, North Carolina, Tennessee and Virginia, according to the Associated Press, and electrical workers were scrambling to address thousands of power outages.

The weather service said the storm could cause up to $1 billion in damage, but the first snowflakes in the nation’s capital earlier Friday were, for many, cause for curiosity.

“It’s awesome,” said Mike Mainey, a 50-year-old Houston resident who commutes to Washington on weekdays. Mainey was shooting video with his smartphone near the White House “for the folks back in Houston, and posting them on Facebook.”

By the early afternoon, most residents were home. Schools throughout the region were closed. One of the nation’s largest subway systems, connecting Virginia and Maryland to the district, planned to shut down at 11 p.m., with many bus lines canceling service much earlier.

Airlines had grounded thousands of flights throughout the region.

Congress delayed votes and the White House canceled medal ceremonies until at least Tuesday, while federal government workers either worked from home or left the office by lunchtime.

The storm was forecast to dump 2 or more feet of snow on Washington and Baltimore, with wind gusts reaching 50 mph. New York, Philadelphia and other major cities in the region could get a foot or more of snow and similar winds. Drivers in parts of Kentucky and North Carolina had already begun experiencing icy roads Friday morning, part of a swath of 15 states, comprising nearly 10 percent of the nation’s population, which was put on notice by the National Weather Service.

“Traveling under these conditions is pretty hazardous,” said Dan Petersen, a meteorologist with the National Weather Service.

Governors as far south as Georgia declared states of emergency Thursday night, with Virginia Gov. Terry McAuliffe issuing an urgent message: “Be prepared to take care of yourself and your family for at least 72 hours, in case roads are blocked and/or there are power outages.”

After initial hesitation and criticism, New Jersey Gov. Chris Christie canceled Friday afternoon and Saturday campaign events in New Hampshire to return home.

New York City was bracing for 12 to 18 inches of snow, high winds and possible coastal flooding. Mayor Bill de Blasio said his city would feel the brunt of the storm on Saturday afternoon.

“Get what you need done today and stay off the roads,” De Blasio said during a news conference, urging drivers to clear the way for 1,800 snowplows.

The National Weather Service also has issued a coastal flood warning for waterfronts in Staten Island, Brooklyn and southern Queens, areas that had been seriously damaged by flooding during Superstorm Sandy in 2012.

In an ironic twist, the blizzard prompted New York to cancel Saturday’s Central Park “Winter Jam,” an annual event where the city brings in snow-making machines for snowboarding and sledding.

Petersen said he expects Washington’s snowfall will rank among the largest of all time in the city, surpassing the third largest blizzard, which left 19 inches in 1979.

“We’re pretty confident it will get that high,” he said. “Now the question is, can it beat the No. 2 and No. 1?”

The record for Washington, 28 inches, was reached in 1922, followed by 20 inches in 1899.

Washington is notoriously ill-prepared for snow, leaving many residents on edge. A dusting on Wednesday night during rush hour created hours of delays, and caused President Obama’s motorcade to slide, as snow crews and commuters were caught off guard, prompting an apology from Bowser and a promise of better preparation before this weekend.

“This is a drop in the bucket so far compared to a place like Chicago,” Joe Zadrozny, visiting from Chicago, said as the first few flakes fell downtown Friday. Zadrozny, 31, said his flight home, scheduled for Sunday, had been postponed and he was uncertain about his dinner reservation.

Mayor Martin Walsh of Boston, who dealt with a record series of blizzards last winter, was one of many leaders who offered to send help. He and other mayors were in Washington late this week for a U.S. Conference of Mayors gathering.

“My Public Works Department in the city of Boston has already contacted me,” he told reporters Thursday. “If we don’t get hit with the snow that’s [going to] hit in Washington... I’m going to offer to (Bowser) if she needs these snow blowers to come to the city to help her, we will help.”

“I feel bad,” he said. “I’m going to hopefully watch it on TV and not look out the window and see it.”

Several homeless men huddled in a partially covered subway entrance said they planned to head to a shelter later in the day.

But Rafael Caban, a 53-year-old who said he had been living on the streets since 1998, said he had refused when an outreach worker came by earlier in the day to warn him.

“I’m used to this weather,” he said. “I’m from New York City. I love this weather.”

Supermarkets and hardware stores have been crowded for days while CVS, the pharmacy chain, used automated phone calls to warn customers to stock enough prescription drugs in case they become housebound for several days. Utility companies were also calling customers to warn against downed power lines and other safety hazards.

Convenience stores ran out of cat food, bank machines ran out of cash, and toy stores ran out of sleds. But Whole Foods still had caviar on the shelves, offering a two-for-one discount at one location. “It’s like a hurricane, right?” said Jessica Parrot, 33, who had just moved to Washington on Monday from Melbourne, Fla., and was doing some sightseeing. “People party. There’s not much you can do. ... As long as my grandma stays warm.”

Despite the concern, or perhaps because of it, downtown Washington was especially quiet during rush hour Friday. There were no winds and the streets were dry.

Many crews had begun preparing roads with brine. Mayor Allison Silberberg of nearby Alexandria, Va., said she had just returned home from buying more milk and water. More than 50 snowplows in her city were pretreating the roads.

Like other local officials, she was urging people to stay home and prepare to remain there until early next week if necessary.

“It’s absolutely beautiful here when it snows. Now, this is a lot of snow here at once,” Silberberg said. “It’s a great time to read a book or catch up on some filing. We just need people to stay off the roads.”