A powerful storm will pound the Northeast with drenching rain, howling winds and surging waves for a second day Saturday.

The nor’easter has already killed at least five people, prompted the cancellation of more than 3,300 flights, snarled ground traffic and knocked out power to more than 1 million customers — with more than 440,000 of them in Massachusetts. Virginia had at least 301,671 customers without power, and the Washington, D.C., area counted over 154,000 people without power.

Massachusetts is taking the brunt of the storm, which hit Friday and is not expected to ease up until midday Saturday.

High tides powered coastal flooding in Boston and other towns, leaving city streets awash for the second time since a massive nor’easter in early January. Record-setting high tides might strike Boston Harbor late Friday night and late Saturday morning.

Kayakers paddled down Boston streets and national guardsmen rescued 50 people from their homes in nearby Quincy, sometimes carrying them to safety in the scoopers of front-end loaders, CNN affiliate WBZ reported. Twenty-two million people were under a coastal flooding warning as of Friday.

“I’m fortunate to get rescued,” Christine Way-Cotter of Quincy told WBZ. “Our house is lifted so, like, nothing came into our first floor but our whole basement is probably 6 feet under water.”

Massachusetts Gov. Charlie Baker said he has called in the National Guard and urged vigilance.

“Do not ride out the storm if you are told to evacuate,” Baker said.

People who lost power won’t get it back quickly.

“People in these homes need to plan for a prolonged outage,” Kurt Schwartz, director of the Massachusetts Emergency Management Agency, said at a Friday night news conference. “This is a multi-day restoration event.”

“This is one of the more extreme storms in recent memory in terms of coastal flooding and damaging wind potential along the coast, but also includes heavy wet snow and heavy rain as important factors,” MEMA said.

At least five people have died, according to authorities: a 77-year-old woman in Kingsville, Maryland; an 11-year-old boy in Putnam County, New York; a 44-year-old man in James City County, Virginia; a juvenile in Chesterfield County, Virginia; and a Newport, Rhode Island, man who was in his 70s. All were killed by falling trees.

The storm morphed into a “bomb cyclone” late Friday morning when it underwent so-called bombogenesis, signaled by an extreme drop in atmospheric pressure.

“Since 10 a.m., Thursday until now, this storm has rapidly dropped in pressure, officially passing the definition of 24 millibars in 24 hours,” CNN meteorologist Judson Jones said Friday morning. “It continues to strengthen.”

More than 3,000 flights canceled

More than 3,000 US flights have been canceled, including hundreds at the busiest Northeast airports in Boston, Philadelphia and New York, the flight-tracking website FlightAware.com posted Friday.

One plane’s bumpy descent into the Washington area left passengers and crew nauseated, according to a pilot’s report tweeted by the Aviation Weather Center.

Airlines, including Delta, United and Southwest, are offering fee waivers for flight cancellations or changes involving affected airports. Airports on the East Coast have been experiencing delays and ground stops, the Federal Aviation Administration said.

Amtrak also announced it had suspended train service between New York and Boston. Amtrak announced overnight that it would resume “modified” service on its Northeast Corridor between Washington and New York City at 6:20 a.m. ET Saturday, and would also resume service between New York and Boston beginning at 8:40 a.m.

In the Washington area, federal offices didn’t open Friday, schools closed and trash collection was suspended. The wind even directed its wrath at the Capitol, blowing out a window on the west front over the Olmstead Terrace, an official from the Architect of the Capitol office said.

As the high tide advanced in New England, authorities warned coastal residents to be ready to evacuate.

Michelle Shaffer, 45, of Hull, Massachusetts evacuated Thursday night to higher ground, she told CNN affiliate WCVB. Shaffer lost her appliances in the last storm and expected another pounding.

“This storm is going to be worse,” she told WCVB, “because it’s going over three high tides.”

New York Gov. Andrew Cuomo said “March is coming in like a lion.”

Heavy snow and strong winds already had caused power outages upstate, Cuomo said late Friday morning. He issued a travel advisory for all areas north of New York City “so plows, utility crews and first responders are able to do their jobs.”

“If you do not have to travel today,” he said, “I encourage you to stay off the roads.”

Here’s what else to expect:

Coastal flooding

With the moon full, the tide is at its highest point of the month, and the storm surge could drive as much as 4 feet of water into coastal neighborhoods, CNN meteorologists said. Massachusetts emergency officials said tides “will be astronomically high” in the next few days.

Boston Harbor, which has only seen tides above 15 feet twice — in 1978 and in January, during the last bomb cyclone — might see the tide at that level when high tides occur late Friday night and late Saturday morning, Jones said.

A high tide that occurred late Friday morning came up a little short, reaching 14.67 feet, but still sent water sloshing through the streets of East Boston.

“I encourage all residents to be mindful of the storm and encourage employers to take the weather into consideration, which will mostly impact the coastal areas of our city,” Boston Mayor Marty Walsh said.

The storm is moving slowly, and the wind, rain and flood effects will linger for days. Parts of eastern Long Island and eastern Massachusetts could get up to 5 inches of rain through Saturday. The rest of the region could see 2 to 4 inches of rain. A foot of snow has already fallen in parts of eastern Massachusetts .

Strong winds

Winds will be so ferocious that the Port Authority of New York and New Jersey is securing cranes at a LaGuardia Airport construction project. It’s also making plans to use buses if trains at JFK or Newark airports must stop because of wind.

In Boston, high wind warnings are in effect through Saturday morning, when winds could whip up to 65 mph. New Jersey officials say high winds may affect trees and power lines.

Barges carrying construction materials broke loose from their moorings near the Tappan Zee Bridge, which crosses the Hudson River, said Laura Ware, public involvement manager for Tappan Zee Constructors LLC.

“Barges associated with the project are equipped with GPS tracking devices and immediately transmitted notifications to our management team when they traveled beyond project limits,” she said. “TZC tug boats were immediately dispatched to recover the barges.”

Snow

Any snow that falls will be heavy and wet, likely to bring down trees and power lines, and cause power outages.

Major cities in the Northeast, such as Philadelphia and New York, may get a wintry mix of snow, rain and sleet, with no snow accumulation forecast.

Inland New England is more likely to get snow, with a foot possible in upstate New York and western Massachusetts. Some areas around Buffalo in western New York have reported 17 inches already, and locations in upstate New York could approach 2 feet.

“Heavy, wet snow fell overnight and snow will continue into the evening hours tonight,” Cuomo said in a statement, describing conditions statewide. “Snow will turn drier and lighter and combined with strong winds, will cause dangerous conditions making driving extremely hazardous from blowing and drifting snow.”