Tens of millions of Americans — from Washington, D.C. to the state of Maine — braced for up to two feet (60 cm) of snow in some areas.
The National Weather Service (NWS) warned that blizzard conditions would “quickly materialize,” making travel extremely dangerous.
Snowfall was forecast at a rate of two to three inches per hour at the height of the storm, with nearly 54 million people in its projected path.
By Sunday evening, heavy snow had already reduced visibility across New York City, with parts of Wall Street barely visible from Brooklyn.
Authorities warned of potential power outages due to heavy snow accumulation and wind gusts of up to 60 miles (100 km) per hour.
In neighboring New Jersey, more than 22,000 customers were reported without electricity.
Mayor Mamdani declared that streets, highways, and bridges in the city would close from 9:00 pm Sunday until noon Monday, citing the scale of the storm as unprecedented in the past decade. Essential workers and emergency travel were exempt from the ban.
Meanwhile, New Jersey Governor Mikie Sherrill declared a state of emergency, and Boston Mayor Michelle Wu closed public schools and municipal buildings ahead of the storm’s peak.
Forecasters also warned of possible coastal flooding from Delaware to Massachusetts, compounding the risk.
New York Governor Kathy Hochul cautioned residents that “the worst is yet to come,” urging them to stock up on essentials and remain indoors.