NEW YORK - New York Mayor Zohran Mamdani ordered the shutdown of the city's entire traffic network for all but emergency travel as a massive snowstorm began to hit the northeast United States.
Tens of millions of Americans from the US capital Washington to the northern state of Maine prepared for up to 60cm of snow forecast in some areas.
The National Weather Service (NWS) said blizzard conditions would "quickly materialise" from Maryland up to southeastern New England, making travel "extremely treacherous."
Snow could fall at a rate of two to three inches per hour at the peak of the storm, with nearly 54 million people in its path, it said.
On Sunday evening, the storm had already begun to hit New York, slashing visibility to the extent that the skyscrapers of Wall Street were barely visible from the adjacent borough of Brooklyn.
Power outages are likely, due to heavy snow and strong wind gusts, forecasters said. As of 7:30 pm local time (0030 GMT), at least 22,895 customers were without power in the state of New Jersey, according to tracking website poweroutage.us.
In New York, which has more than eight million people, Mamdani said streets, highways and bridges would be shut down from 9:00 pm Sunday until noon Monday.
"New York City has not faced a storm of this scale in the last decade," he said, explaining the state of emergency. "We are asking New Yorkers to avoid all non-essential travel."
The ban will not apply to essential workers or New Yorkers needing to travel due to emergencies.
The NWS warned heavy snow, high winds and low visibility were "expected to cause dangerous to impossible travel" conditions.
Gusts of up to 100km/h were expected late Sunday and into Monday, the NWS said.
New Jersey Governor Mikie Sherrill declared a state of emergency beginning midday Sunday, freeing up funds and allowing the swift deployment of resources to address the weather crisis.
In Boston, Mayor Michelle Wu closed all public schools and municipal buildings 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," Wu said.
The NWS said "moderate to major" coastal flooding affecting waterfront roads and properties was possible from Delaware up to Cape Cod in Massachusetts.
The storm comes just weeks after the region recovered from another devastating winter weather system that was linked to more than 100 deaths.