Residents in New York City and New Jersey were hunkering down as a severe snowstorm swept across the northeastern United States late on Sunday, prompting a travel ban.

Blizzard warnings were issued for New York City and Long Island, Boston and coastal areas in Delaware, Maryland, New Jersey, Connecticut, Rhode Island and Massachusetts.

A state of emergency has been declared in New York state, New Jersey, Delaware, Rhode Island, Connecticut and Massachusetts.

The National Weather Service (NWS) said that blizzard conditions would "quickly materialize" from Maryland up to southeastern New England, making travel "extremely treacherous."

It added that 1 to 2 feet (30 to 60 centimeters) of snow was possible in many areas, accompanied with heavy winds.

The NWS said that nearly 54 million people are estimated to be in the path of the storm as officials throughout the region urged residents to avoid travel.

Meanwhile, visibility in many areas was expected to be 400 meters or less, the weather service said.

Massive snowstorm paralyzes New York

The storm had already begun to hit New York Ciy on Sunday evening.

The skyscrapers of Wall Street could barely be seen from the nearby borough of Brooklyn amid deteriorating visibility.

Mayor Zohran Mamdani ordered a ban on non-emergency travel on all streets from 9 pm ET (3 am CET) on Sunday until Monday at noon.

"New York City has not faced a storm of this scale in the last decade," he said.

Reports said that outreach workers were urging homeless New Yorkers to go into shelters and warming centers.

Thousands of flights were cancelled and thousands of others were delayed across the country on Sunday, tracking website FlightAware showed.

Theater performances on New York's Broadway were canceled while schools, municipal libraries, and other institutions were shut on Monday.

State of emergency in New Jersey

In New Jersey, Governor Mikie Sherrill declared a state of emergency from midday Sunday, freeing up funds and allowing the deployment of resources to deal with the weather crisis.

"We're expecting blizzard conditions, heavy snow, and high winds across the state – as well as coastal flooding," she wrote on X.

Boston ordered public schools and municipal buildings to shut down on Monday.

"We ask everyone to plan ahead, stay safe and warm, and stay off the roads to help our public works and public safety efforts," the city's Mayor Michelle Wu said.

Forecasters also warned of power outages from the heavy snowfall and powerful gusts of wind.

At least 22,895 customers were without power in the state of New Jersey at 7.30 pm ET (1. 30 pm CET), according to tracking website poweroutage.us.

Edited by: Elizabeth Schumacher